diff options
| -rw-r--r-- | COPYING | 339 | ||||
| -rw-r--r-- | Makefile | 46 | ||||
| -rw-r--r-- | bmp.h | 103 | ||||
| -rw-r--r-- | stegmp.c | 180 |
4 files changed, 668 insertions, 0 deletions
@@ -0,0 +1,339 @@ +GNU GENERAL PUBLIC LICENSE + Version 2, June 1991 + + Copyright (C) 1989, 1991 Free Software Foundation, Inc., <http://fsf.org/> + 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + Everyone is permitted to copy and distribute verbatim copies + of this license document, but changing it is not allowed. + + Preamble + + The licenses for most software are designed to take away your +freedom to share and change it. By contrast, the GNU General Public +License is intended to guarantee your freedom to share and change free +software--to make sure the software is free for all its users. This +General Public License applies to most of the Free Software +Foundation's software and to any other program whose authors commit to +using it. (Some other Free Software Foundation software is covered by +the GNU Lesser General Public License instead.) You can apply it to +your programs, too. + + When we speak of free software, we are referring to freedom, not +price. Our General Public Licenses are designed to make sure that you +have the freedom to distribute copies of free software (and charge for +this service if you wish), that you receive source code or can get it +if you want it, that you can change the software or use pieces of it +in new free programs; and that you know you can do these things. + + To protect your rights, we need to make restrictions that forbid +anyone to deny you these rights or to ask you to surrender the rights. +These restrictions translate to certain responsibilities for you if you +distribute copies of the software, or if you modify it. + + For example, if you distribute copies of such a program, whether +gratis or for a fee, you must give the recipients all the rights that +you have. You must make sure that they, too, receive or can get the +source code. And you must show them these terms so they know their +rights. + + We protect your rights with two steps: (1) copyright the software, and +(2) offer you this license which gives you legal permission to copy, +distribute and/or modify the software. + + Also, for each author's protection and ours, we want to make certain +that everyone understands that there is no warranty for this free +software. If the software is modified by someone else and passed on, we +want its recipients to know that what they have is not the original, so +that any problems introduced by others will not reflect on the original +authors' reputations. + + Finally, any free program is threatened constantly by software +patents. We wish to avoid the danger that redistributors of a free +program will individually obtain patent licenses, in effect making the +program proprietary. To prevent this, we have made it clear that any +patent must be licensed for everyone's free use or not licensed at all. + + The precise terms and conditions for copying, distribution and +modification follow. + + GNU GENERAL PUBLIC LICENSE + TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION + + 0. This License applies to any program or other work which contains +a notice placed by the copyright holder saying it may be distributed +under the terms of this General Public License. The "Program", below, +refers to any such program or work, and a "work based on the Program" +means either the Program or any derivative work under copyright law: +that is to say, a work containing the Program or a portion of it, +either verbatim or with modifications and/or translated into another +language. (Hereinafter, translation is included without limitation in +the term "modification".) Each licensee is addressed as "you". + +Activities other than copying, distribution and modification are not +covered by this License; they are outside its scope. The act of +running the Program is not restricted, and the output from the Program +is covered only if its contents constitute a work based on the +Program (independent of having been made by running the Program). +Whether that is true depends on what the Program does. + + 1. You may copy and distribute verbatim copies of the Program's +source code as you receive it, in any medium, provided that you +conspicuously and appropriately publish on each copy an appropriate +copyright notice and disclaimer of warranty; keep intact all the +notices that refer to this License and to the absence of any warranty; +and give any other recipients of the Program a copy of this License +along with the Program. + +You may charge a fee for the physical act of transferring a copy, and +you may at your option offer warranty protection in exchange for a fee. + + 2. You may modify your copy or copies of the Program or any portion +of it, thus forming a work based on the Program, and copy and +distribute such modifications or work under the terms of Section 1 +above, provided that you also meet all of these conditions: + + a) You must cause the modified files to carry prominent notices + stating that you changed the files and the date of any change. + + b) You must cause any work that you distribute or publish, that in + whole or in part contains or is derived from the Program or any + part thereof, to be licensed as a whole at no charge to all third + parties under the terms of this License. + + c) If the modified program normally reads commands interactively + when run, you must cause it, when started running for such + interactive use in the most ordinary way, to print or display an + announcement including an appropriate copyright notice and a + notice that there is no warranty (or else, saying that you provide + a warranty) and that users may redistribute the program under + these conditions, and telling the user how to view a copy of this + License. (Exception: if the Program itself is interactive but + does not normally print such an announcement, your work based on + the Program is not required to print an announcement.) + +These requirements apply to the modified work as a whole. If +identifiable sections of that work are not derived from the Program, +and can be reasonably considered independent and separate works in +themselves, then this License, and its terms, do not apply to those +sections when you distribute them as separate works. But when you +distribute the same sections as part of a whole which is a work based +on the Program, the distribution of the whole must be on the terms of +this License, whose permissions for other licensees extend to the +entire whole, and thus to each and every part regardless of who wrote it. + +Thus, it is not the intent of this section to claim rights or contest +your rights to work written entirely by you; rather, the intent is to +exercise the right to control the distribution of derivative or +collective works based on the Program. + +In addition, mere aggregation of another work not based on the Program +with the Program (or with a work based on the Program) on a volume of +a storage or distribution medium does not bring the other work under +the scope of this License. + + 3. You may copy and distribute the Program (or a work based on it, +under Section 2) in object code or executable form under the terms of +Sections 1 and 2 above provided that you also do one of the following: + + a) Accompany it with the complete corresponding machine-readable + source code, which must be distributed under the terms of Sections + 1 and 2 above on a medium customarily used for software interchange; or, + + b) Accompany it with a written offer, valid for at least three + years, to give any third party, for a charge no more than your + cost of physically performing source distribution, a complete + machine-readable copy of the corresponding source code, to be + distributed under the terms of Sections 1 and 2 above on a medium + customarily used for software interchange; or, + + c) Accompany it with the information you received as to the offer + to distribute corresponding source code. (This alternative is + allowed only for noncommercial distribution and only if you + received the program in object code or executable form with such + an offer, in accord with Subsection b above.) + +The source code for a work means the preferred form of the work for +making modifications to it. For an executable work, complete source +code means all the source code for all modules it contains, plus any +associated interface definition files, plus the scripts used to +control compilation and installation of the executable. However, as a +special exception, the source code distributed need not include +anything that is normally distributed (in either source or binary +form) with the major components (compiler, kernel, and so on) of the +operating system on which the executable runs, unless that component +itself accompanies the executable. + +If distribution of executable or object code is made by offering +access to copy from a designated place, then offering equivalent +access to copy the source code from the same place counts as +distribution of the source code, even though third parties are not +compelled to copy the source along with the object code. + + 4. You may not copy, modify, sublicense, or distribute the Program +except as expressly provided under this License. Any attempt +otherwise to copy, modify, sublicense or distribute the Program is +void, and will automatically terminate your rights under this License. +However, parties who have received copies, or rights, from you under +this License will not have their licenses terminated so long as such +parties remain in full compliance. + + 5. You are not required to accept this License, since you have not +signed it. However, nothing else grants you permission to modify or +distribute the Program or its derivative works. These actions are +prohibited by law if you do not accept this License. Therefore, by +modifying or distributing the Program (or any work based on the +Program), you indicate your acceptance of this License to do so, and +all its terms and conditions for copying, distributing or modifying +the Program or works based on it. + + 6. Each time you redistribute the Program (or any work based on the +Program), the recipient automatically receives a license from the +original licensor to copy, distribute or modify the Program subject to +these terms and conditions. You may not impose any further +restrictions on the recipients' exercise of the rights granted herein. +You are not responsible for enforcing compliance by third parties to +this License. + + 7. If, as a consequence of a court judgment or allegation of patent +infringement or for any other reason (not limited to patent issues), +conditions are imposed on you (whether by court order, agreement or +otherwise) that contradict the conditions of this License, they do not +excuse you from the conditions of this License. If you cannot +distribute so as to satisfy simultaneously your obligations under this +License and any other pertinent obligations, then as a consequence you +may not distribute the Program at all. For example, if a patent +license would not permit royalty-free redistribution of the Program by +all those who receive copies directly or indirectly through you, then +the only way you could satisfy both it and this License would be to +refrain entirely from distribution of the Program. + +If any portion of this section is held invalid or unenforceable under +any particular circumstance, the balance of the section is intended to +apply and the section as a whole is intended to apply in other +circumstances. + +It is not the purpose of this section to induce you to infringe any +patents or other property right claims or to contest validity of any +such claims; this section has the sole purpose of protecting the +integrity of the free software distribution system, which is +implemented by public license practices. Many people have made +generous contributions to the wide range of software distributed +through that system in reliance on consistent application of that +system; it is up to the author/donor to decide if he or she is willing +to distribute software through any other system and a licensee cannot +impose that choice. + +This section is intended to make thoroughly clear what is believed to +be a consequence of the rest of this License. + + 8. If the distribution and/or use of the Program is restricted in +certain countries either by patents or by copyrighted interfaces, the +original copyright holder who places the Program under this License +may add an explicit geographical distribution limitation excluding +those countries, so that distribution is permitted only in or among +countries not thus excluded. In such case, this License incorporates +the limitation as if written in the body of this License. + + 9. The Free Software Foundation may publish revised and/or new versions +of the General Public License from time to time. Such new versions will +be similar in spirit to the present version, but may differ in detail to +address new problems or concerns. + +Each version is given a distinguishing version number. If the Program +specifies a version number of this License which applies to it and "any +later version", you have the option of following the terms and conditions +either of that version or of any later version published by the Free +Software Foundation. If the Program does not specify a version number of +this License, you may choose any version ever published by the Free Software +Foundation. + + 10. If you wish to incorporate parts of the Program into other free +programs whose distribution conditions are different, write to the author +to ask for permission. For software which is copyrighted by the Free +Software Foundation, write to the Free Software Foundation; we sometimes +make exceptions for this. Our decision will be guided by the two goals +of preserving the free status of all derivatives of our free software and +of promoting the sharing and reuse of software generally. + + NO WARRANTY + + 11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY +FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN +OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES +PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED +OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF +MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS +TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE +PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, +REPAIR OR CORRECTION. + + 12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING +WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR +REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, +INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING +OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED +TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY +YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER +PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE +POSSIBILITY OF SUCH DAMAGES. + + END OF TERMS AND CONDITIONS + + How to Apply These Terms to Your New Programs + + If you develop a new program, and you want it to be of the greatest +possible use to the public, the best way to achieve this is to make it +free software which everyone can redistribute and change under these terms. + + To do so, attach the following notices to the program. It is safest +to attach them to the start of each source file to most effectively +convey the exclusion of warranty; and each file should have at least +the "copyright" line and a pointer to where the full notice is found. + + {description} + Copyright (C) {year} {fullname} + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License along + with this program; if not, write to the Free Software Foundation, Inc., + 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + +Also add information on how to contact you by electronic and paper mail. + +If the program is interactive, make it output a short notice like this +when it starts in an interactive mode: + + Gnomovision version 69, Copyright (C) year name of author + Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'. + This is free software, and you are welcome to redistribute it + under certain conditions; type `show c' for details. + +The hypothetical commands `show w' and `show c' should show the appropriate +parts of the General Public License. Of course, the commands you use may +be called something other than `show w' and `show c'; they could even be +mouse-clicks or menu items--whatever suits your program. + +You should also get your employer (if you work as a programmer) or your +school, if any, to sign a "copyright disclaimer" for the program, if +necessary. Here is a sample; alter the names: + + Yoyodyne, Inc., hereby disclaims all copyright interest in the program + `Gnomovision' (which makes passes at compilers) written by James Hacker. + + {signature of Ty Coon}, 1 April 1989 + Ty Coon, President of Vice + +This General Public License does not permit incorporating your program into +proprietary programs. If your program is a subroutine library, you may +consider it more useful to permit linking proprietary applications with the +library. If this is what you want to do, use the GNU Lesser General +Public License instead of this License. diff --git a/Makefile b/Makefile new file mode 100644 index 0000000..5724b71 --- /dev/null +++ b/Makefile @@ -0,0 +1,46 @@ +## Copyright (C) 2014 Olivier Gayot <duskcoder@gmail.com> +## +## This program is free software; you can redistribute it and/or modify +## it under the terms of the GNU General Public License as published by +## the Free Software Foundation; either version 2 of the License, or +## (at your option) any later version. +## +## This program is distributed in the hope that it will be useful, +## but WITHOUT ANY WARRANTY; without even the implied warranty of +## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +## GNU General Public License for more details. +## +## You should have received a copy of the GNU General Public License along +## with this program; if not, write to the Free Software Foundation, Inc., +## 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + +CC ?= gcc +CFLAGS += -W -Wall -std=gnu99 -Wextra +CFLAGS += -D _XOPEN_SOURCE -D _DEFAULT_SOURCE +NAME = stegmp +SRC = stegmp.c + +all: depend $(NAME) + +depend: .depend + +.depend: $(SRC) + @$(RM) .depend + @$(CC) $(CFLAGS) -MM $^ > .depend + +include .depend + +OBJ = $(SRC:.c=.o) + +$(NAME): $(OBJ) + $(CC) -o $@ $^ $(LDFLAGS) + +clean: + $(RM) $(OBJ) + +fclean: clean + $(RM) $(NAME) + +re: fclean all + +.PHONY: all depend clean fclean all re @@ -0,0 +1,103 @@ +/* + * Copyright (C) 2014 Olivier Gayot <duskcoder@gmail.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + */ + +#ifndef BMP_H +#define BMP_H + +#include <endian.h> + +#include <stdint.h> + +struct packed_bmp_header { + uint16_t magic; + uint32_t bmp_size; + uint16_t reserved; + uint16_t reserved2; + uint32_t data_offset; +} __attribute__((packed)); + +struct bitmap { + uint32_t size; + uint32_t data_offset; + uint32_t width; + uint32_t height; + uint16_t bpp; +}; + +/* Windows BITMAPINFOHEADER */ +struct bitmap_info_header { + uint32_t header_size; + uint32_t bmp_width; + uint32_t bmp_height; + uint16_t planes; + uint16_t bpp; + uint32_t compression; + uint32_t img_size; + uint32_t horizontal_res; + uint32_t vertical_res; + uint32_t palette; + uint32_t important_colors; +} __attribute((packed)); + +enum { +#if __BYTE_ORDER == __BIG_ENDIAN + BMP_MAGIC_BM = 0x424D, + BMP_MAGIC_BA = 0x4241, + BMP_MAGIC_CI = 0x4349, + BMP_MAGIC_CP = 0x4350, + BMP_MAGIC_IC = 0x4943, + BMP_MAGIC_PT = 0x5054, +#elif __BYTE_ORDER == __LITTLE_ENDIAN + BMP_MAGIC_BM = 0x4D42, + BMP_MAGIC_BA = 0x4142, + BMP_MAGIC_CI = 0x4943, + BMP_MAGIC_CP = 0x5043, + BMP_MAGIC_IC = 0x4349, + BMP_MAGIC_PT = 0x5450, +#endif +}; + +enum { + /* bmp header */ + BMP_ESUCCESS, + BMP_ENOTBMP, + BMP_ENOTSUPP, + + BMP_EINVALSIZ, + + BMP_EINVALBPP, + + BMP_ERRNO_COUNT, +}; + +const char *bmp_error_string[] = { + [BMP_ESUCCESS] = "Success", + [BMP_ENOTBMP] = "File is not a BMP", + [BMP_ENOTSUPP] = "File format not supported", + [BMP_EINVALSIZ] = "Inconsistent file size", + [BMP_EINVALBPP] = "Invalid BPP value", +}; + +int bmp_errno = BMP_ESUCCESS; + +static inline const char *bmp_strerror(int err) +{ + return bmp_error_string[err]; +} + +#endif /* BMP_H */ diff --git a/stegmp.c b/stegmp.c new file mode 100644 index 0000000..b1f42a8 --- /dev/null +++ b/stegmp.c @@ -0,0 +1,180 @@ +/* + * Copyright (C) 2014 Olivier Gayot <duskcoder@gmail.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + */ + +#include <sys/mman.h> +#include <sys/types.h> +#include <sys/stat.h> +#include <unistd.h> + +#include <string.h> +#include <stdio.h> + +#include "bmp.h" + +static int stegmp_parse_windows_bitmap_info_header(const unsigned char *addr, + size_t size, struct bitmap *bmpp) +{ + struct bitmap_info_header info_header; + + if (size < sizeof(typeof(info_header))) { + bmp_errno = BMP_EINVALSIZ; + return -1; + } + + info_header = *((typeof(info_header) *)addr); + + switch (info_header.bpp) { + case 8: + case 16: + case 24: + case 32: + bmpp->bpp = info_header.bpp; + break; + default: + bmp_errno = BMP_EINVALBPP; + return -1; + } + + /* TODO check the compression type */ + + bmpp->width = info_header.bmp_width; + bmpp->height = info_header.bmp_height; + + return 0; +} + +/* guess which type of DIB header it is and handle it or not */ +static int stegmp_parse_dib_header(const unsigned char *addr, size_t size, + struct bitmap *bmpp) +{ + uint32_t dib_size; + + if (size < sizeof(typeof(dib_size))) { + bmp_errno = BMP_EINVALSIZ; + return -1; + } + + dib_size = *((typeof(dib_size) *)addr); + + switch (dib_size) { + case 12: + case 52: + case 56: + case 64: + case 108: + case 124: + bmp_errno = BMP_ENOTSUPP; + return -1; + + case 40: + return stegmp_parse_windows_bitmap_info_header(addr, size, bmpp); + + default: + bmp_errno = BMP_ENOTBMP; + return -1; + } +} + +/* parse the main header of the bmp file */ +static int stegmp_parse_headers(const unsigned char *addr, size_t orig_size, + struct bitmap *bmpp) +{ + struct packed_bmp_header packed_header; + + if (orig_size < sizeof(packed_header)) { + bmp_errno = BMP_ENOTBMP; + return -1; + } + + packed_header = *((typeof(packed_header) *)addr); + + switch (packed_header.magic) { + case BMP_MAGIC_BM: + break; + + case BMP_MAGIC_BA: + case BMP_MAGIC_CI: + case BMP_MAGIC_CP: + case BMP_MAGIC_IC: + case BMP_MAGIC_PT: + bmp_errno = BMP_ENOTSUPP; + return -1; + default: + bmp_errno = BMP_ENOTBMP; + return -1; + } + + if (packed_header.bmp_size != orig_size) { + bmp_errno = BMP_EINVALSIZ; + return -1; + } + + bmpp->data_offset = packed_header.data_offset; + bmpp->size = packed_header.bmp_size; + + stegmp_parse_dib_header(addr + sizeof(packed_header), orig_size, bmpp); + + return 0; +} + +static int stegmp(const char *filename) +{ + void *addr; + struct stat stat; + struct bitmap bmp; + FILE *fh = fopen(filename, "r+"); + + if (fh == NULL) { + fprintf(stderr, "%s: %m\n", filename); + return -1; + } + + fstat(fileno(fh), &stat); + addr = mmap(NULL, stat.st_size, PROT_READ | PROT_WRITE, MAP_PRIVATE, + fileno(fh), 0); + + if (addr == MAP_FAILED) { + fprintf(stderr, "%s: %m\n", filename); + fclose(fh); + return -1; + } + + /* retrieve the required information (i.e. width, height, bpp .. ) */ + if (stegmp_parse_headers(addr, stat.st_size, &bmp) >= 0) { + /* TODO */ + } else { + fprintf(stderr, "unable to parse headers: %s\n", + bmp_strerror(bmp_errno)); + } + + munmap(addr, stat.st_size); + fclose(fh); + + return 0; +} + +int main(int argc, char *argv[]) +{ + /* we need a file passed as argument since we want to map it */ + if (argc < 2) { + fprintf(stderr, "usage: %s BMP\n", argv[0]); + return -1; + } + + return stegmp(argv[1]); +} |