kernel.git/fs/binfmt_elf_fdpic.c, branch linux-2.6.37.y

binfmt_elf_fdpic: Fix clear_user() error handling

2010-06-01T15:11:06Z

clear_user() returns the number of bytes that could not be copied rather than an error code. So we should return -EFAULT rather than directly returning the results. Without this patch, positive values may be returned to elf_fdpic_map_file() and the following error handlings do not function as expected. 1. ret = elf_fdpic_map_file_constdisp_on_uclinux(params, file, mm); if (ret < 0) return ret; 2. ret = elf_fdpic_map_file_by_direct_mmap(params, file, mm); if (ret < 0) return ret; Signed-off-by: Takuya Yoshikawa Signed-off-by: David Howells Acked-by: Mike Frysinger CC: Alexander Viro CC: Andrew Morton CC: Daisuke HATAYAMA CC: Paul Mundt Signed-off-by: Linus Torvalds

Remove redundant check for CONFIG_MMU

2010-04-27T16:01:26Z

The checks for CONFIG_MMU at this location are duplicated as all the code is located inside a #ifndef CONFIG_MMU block. So the first conditional block will always be included while the second never will. Signed-off-by: Christoph Egger Signed-off-by: David Howells Signed-off-by: Linus Torvalds

FDPIC: For-loop in elf_core_vma_data_size() is incorrect

2010-03-24T23:43:29Z

Fix an incorrect for-loop in elf_core_vma_data_size(). The advance-pointer statement lacks an assignment: CC fs/binfmt_elf_fdpic.o fs/binfmt_elf_fdpic.c: In function 'elf_core_vma_data_size': fs/binfmt_elf_fdpic.c:1593: warning: statement with no effect Signed-off-by: David Howells Signed-off-by: Linus Torvalds

Merge branch 'for-next' into for-linus

2010-03-08T15:55:37Z

Conflicts: Documentation/filesystems/proc.txt arch/arm/mach-u300/include/mach/debug-macro.S drivers/net/qlge/qlge_ethtool.c drivers/net/qlge/qlge_main.c drivers/net/typhoon.c

coredump: pass mm->flags as a coredump parameter for consistency

2010-03-06T19:26:46Z

Pass mm->flags as a coredump parameter for consistency. --- 1787 if (mm->core_state || !get_dumpable(mm)) { <- (1) 1788 up_write(&mm->mmap_sem); 1789 put_cred(cred); 1790 goto fail; 1791 } 1792 [...] 1798 if (get_dumpable(mm) == 2) { /* Setuid core dump mode */ <-(2) 1799 flag = O_EXCL; /* Stop rewrite attacks */ 1800 cred->fsuid = 0; /* Dump root private */ 1801 } --- Since dumpable bits are not protected by lock, there is a chance to change these bits between (1) and (2). To solve this issue, this patch copies mm->flags to coredump_params.mm_flags at the beginning of do_coredump() and uses it instead of get_dumpable() while dumping core. This copy is also passed to binfmt->core_dump, since elf*_core_dump() uses dump_filter bits in mm->flags. [akpm@linux-foundation.org: fix merge] Signed-off-by: Masami Hiramatsu Acked-by: Roland McGrath Cc: Hidehiro Kawai Cc: Oleg Nesterov Cc: Ingo Molnar Reviewed-by: KOSAKI Motohiro Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

elf coredump: add extended numbering support

2010-03-06T19:26:46Z

The current ELF dumper implementation can produce broken corefiles if program headers exceed 65535. This number is determined by the number of vmas which the process have. In particular, some extreme programs may use more than 65535 vmas. (If you google max_map_count, you can find some users facing this problem.) This kind of program never be able to generate correct coredumps. This patch implements ``extended numbering'' that uses sh_info field of the first section header instead of e_phnum field in order to represent upto 4294967295 vmas. This is supported by AMD64-ABI(http://www.x86-64.org/documentation.html) and Solaris(http://docs.sun.com/app/docs/doc/817-1984/). Of course, we are preparing patches for gdb and binutils. Signed-off-by: Daisuke HATAYAMA Cc: "Luck, Tony" Cc: Jeff Dike Cc: David Howells Cc: Greg Ungerer Cc: Roland McGrath Cc: Oleg Nesterov Cc: Ingo Molnar Cc: Alexander Viro Cc: Andi Kleen Cc: Alan Cox Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

elf coredump: make offset calculation process and writing process explicit

2010-03-06T19:26:46Z

By the next patch, elf_core_dump() and elf_fdpic_core_dump() will support extended numbering and so will produce the corefiles with section header table in a special case. The problem is the process of writing a file header offset of the section header table into e_shoff field of the ELF header. ELF header is positioned at the beginning of the corefile, while section header at the end. So, we need to take which of the following ways: 1. Seek backward to retry writing operation for ELF header after writing process for a whole part 2. Make offset calculation process and writing process totally sequential The clause 1. is not always possible: one cannot assume that file system supports seek function. Consider the no_llseek case. Therefore, this patch adopts the clause 2. Signed-off-by: Daisuke HATAYAMA Cc: "Luck, Tony" Cc: Jeff Dike Cc: David Howells Cc: Greg Ungerer Cc: Roland McGrath Cc: Oleg Nesterov Cc: Ingo Molnar Cc: Alexander Viro Cc: Andi Kleen Cc: Alan Cox Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

elf coredump: replace ELF_CORE_EXTRA_* macros by functions

2010-03-06T19:26:45Z

elf_core_dump() and elf_fdpic_core_dump() use #ifdef and the corresponding macro for hiding _multiline_ logics in functions. This patch removes #ifdef and replaces ELF_CORE_EXTRA_* by corresponding functions. For architectures not implemeonting ELF_CORE_EXTRA_*, we use weak functions in order to reduce a range of modification. This cleanup is for my next patches, but I think this cleanup itself is worth doing regardless of my firnal purpose. Signed-off-by: Daisuke HATAYAMA Cc: "Luck, Tony" Cc: Jeff Dike Cc: David Howells Cc: Greg Ungerer Cc: Roland McGrath Cc: Oleg Nesterov Cc: Ingo Molnar Cc: Alexander Viro Cc: Andi Kleen Cc: Alan Cox Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

coredump: move dump_write() and dump_seek() into a header file

2010-03-06T19:26:45Z

My next patch will replace ELF_CORE_EXTRA_* macros by functions, putting them into other newly created *.c files. Then, each files will contain dump_write(), where each pair of binfmt_*.c and elfcore.c should be the same. So, this patch moves them into a header file with dump_seek(). Also, the patch deletes confusing DUMP_WRITE macros in each files. Signed-off-by: Daisuke HATAYAMA Cc: "Luck, Tony" Cc: Jeff Dike Cc: David Howells Cc: Greg Ungerer Cc: Roland McGrath Cc: Oleg Nesterov Cc: Ingo Molnar Cc: Alexander Viro Cc: Andi Kleen Cc: Alan Cox Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

coredump: unify dump_seek() implementations for each binfmt_*.c

2010-03-06T19:26:45Z

The current ELF dumper can produce broken corefiles if program headers exceed 65535. In particular, the program in 64-bit environment often demands more than 65535 mmaps. If you google max_map_count, then you can find many users facing this problem. Solaris has already dealt with this issue, and other OSes have also adopted the same method as in Solaris. Currently, Sun's document and AMD 64 ABI include the description for the extension, where they call the extension Extended Numbering. See Reference for further information. I believe that linux kernel should adopt the same way as they did, so I've written this patch. I am also preparing for patches of GDB and binutils. How to fix ========== In new dumping process, there are two cases according to weather or not the number of program headers is equal to or more than 65535. - if less than 65535, the produced corefile format is exactly the same as the ordinary one. - if equal to or more than 65535, then e_phnum field is set to newly introduced constant PN_XNUM(0xffff) and the actual number of program headers is set to sh_info field of the section header at index 0. Compatibility Concern ===================== * As already mentioned in Summary, Sun and AMD64 has already adopted this. See Reference. * There are four combinations according to whether kernel and userland tools are respectively modified or not. The next table summarizes shortly for each combination. --------------------------------------------- Original Kernel | Modified Kernel --------------------------------------------- < 65535 | >= 65535 | < 65535 | >= 65535 ------------------------------------------------------------- Original Tools | OK | broken | OK | broken (#) ------------------------------------------------------------- Modified Tools | OK | broken | OK | OK ------------------------------------------------------------- Note that there is no case that `OK' changes to `broken'. (#) Although this case remains broken, O-M behaves better than O-O. That is, while in O-O case e_phnum field would be extremely small due to integer overflow, in O-M case it is guaranteed to be at least 65535 by being set to PN_XNUM(0xFFFF), much closer to the actual correct value than the O-O case. Test Program ============ Here is a test program mkmmaps.c that is useful to produce the corefile with many mmaps. To use this, please take the following steps: $ ulimit -c unlimited $ sysctl vm.max_map_count=70000 # default 65530 is too small $ sysctl fs.file-max=70000 $ mkmmaps 65535 Then, the program will abort and a corefile will be generated. If failed, there are two cases according to the error message displayed. * ``out of memory'' means vm.max_map_count is still smaller * ``too many open files'' means fs.file-max is still smaller So, please change it to a larger value, and then retry it. mkmmaps.c == #include #include #include #include #include int main(int argc, char **argv) { int maps_num; if (argc < 2) { fprintf(stderr, "mkmmaps [number of maps to be created]\n"); exit(1); } if (sscanf(argv[1], "%d", &maps_num) == EOF) { perror("sscanf"); exit(2); } if (maps_num < 0) { fprintf(stderr, "%d is invalid\n", maps_num); exit(3); } for (; maps_num > 0; --maps_num) { if (MAP_FAILED == mmap((void *)NULL, (size_t) 1, PROT_READ, MAP_SHARED | MAP_ANONYMOUS, (int) -1, (off_t) NULL)) { perror("mmap"); exit(4); } } abort(); { char buffer[128]; sprintf(buffer, "wc -l /proc/%u/maps", getpid()); system(buffer); } return 0; } Tested on i386, ia64 and um/sys-i386. Built on sh4 (which covers fs/binfmt_elf_fdpic.c) References ========== - Sun microsystems: Linker and Libraries. Part No: 817-1984-17, September 2008. URL: http://docs.sun.com/app/docs/doc/817-1984 - System V ABI AMD64 Architecture Processor Supplement Draft Version 0.99., May 11, 2009. URL: http://www.x86-64.org/ This patch: There are three different definitions for dump_seek() functions in binfmt_aout.c, binfmt_elf.c and binfmt_elf_fdpic.c, respectively. The only for binfmt_elf.c. My next patch will move dump_seek() into a header file in order to share the same implementations for dump_write() and dump_seek(). As the first step, this patch unify these three definitions for dump_seek() by applying the past commits that have been applied only for binfmt_elf.c. Specifically, the modification made here is part of the following commits: * d025c9db7f31fc0554ce7fb2dfc78d35a77f3487 * 7f14daa19ea36b200d237ad3ac5826ae25360461 This patch does not change a shape of corefiles. Signed-off-by: Daisuke HATAYAMA Cc: "Luck, Tony" Cc: Jeff Dike Cc: David Howells Cc: Greg Ungerer Cc: Roland McGrath Cc: Oleg Nesterov Cc: Ingo Molnar Cc: Alexander Viro Cc: Andi Kleen Cc: Alan Cox Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds