pa-fazil
/
android_bionic
mirror of https://github.com/fazilsheik96/android_bionic.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity
android_bionic/libc/arch-x86_64/syscalls/__fchmodat.S

17 lines
309 B
ArmAsm
Raw Normal View History

Sort the syscalls.mk files, give all generated files the same header. No non-comment changes to the .S files. Change-Id: Iafcfd004c3ea92b64268f80ab16df615b97cefac
2013-10-16 21:27:59 +00:00
/* Generated by gensyscalls.py. Do not edit. */
Stop using the non-uapi <linux/err.h> header file. We only need it for MAX_ERRNO, and it's time we had somewhere to put the little assembler utility macros we've been putting off writing. Change-Id: I9354d2e0dc47c689296a34b5b229fc9ba75f1a83
2013-11-07 18:31:05 +00:00
#include <private/bionic_asm.h>
Regenerate the system call stubs (to get x86_64). This touches the x86 stubs too because arm, x86, and x86_64 now all share the same header (at a source level), which causes a reordering of the #include lines. Change-Id: If9a1e2b2718bd41d8399fea748bce672c513ef84
2013-10-01 20:29:43 +00:00
Add fchmodat(AT_SYMLINK_NOFOLLOW) and fchmod O_PATH support Many libc functions have an option to not follow symbolic links. This is useful to avoid security sensitive code from inadvertantly following attacker supplied symlinks and taking inappropriate action on files it shouldn't. For example, open() has O_NOFOLLOW, chown() has lchown(), stat() has lstat(), etc. There is no such equivalent function for chmod(), such as lchmod(). To address this, POSIX introduced fchmodat(AT_SYMLINK_NOFOLLOW), which is intended to provide a way to perform a chmod operation which doesn't follow symlinks. Currently, the Linux kernel doesn't implement AT_SYMLINK_NOFOLLOW. In GLIBC, attempting to use the AT_SYMLINK_NOFOLLOW flag causes fchmodat to return ENOTSUP. Details are in "man fchmodat". Bionic currently differs from GLIBC in that AT_SYMLINK_NOFOLLOW is silently ignored and treated as if the flag wasn't present. This patch provides a userspace implementation of AT_SYMLINK_NOFOLLOW for bionic. Using open(O_PATH | O_NOFOLLOW), we can provide a way to atomically change the permissions on files without worrying about race conditions. As part of this change, we add support for fchmod on O_PATH file descriptors, because it's relatively straight forward and could be useful in the future. The basic idea behind this implementation comes from https://sourceware.org/bugzilla/show_bug.cgi?id=14578 , specifically comment #10. Change-Id: I1eba0cdb2c509d9193ceecf28f13118188a3cfa7
2015-02-01 03:57:46 +00:00
ENTRY(__fchmodat)
Regenerate the system call stubs (to get x86_64). This touches the x86 stubs too because arm, x86, and x86_64 now all share the same header (at a source level), which causes a reordering of the #include lines. Change-Id: If9a1e2b2718bd41d8399fea748bce672c513ef84
2013-10-01 20:29:43 +00:00
movl $__NR_fchmodat, %eax
syscall
cmpq $-MAX_ERRNO, %rax
jb 1f
negl %eax
movl %eax, %edi
Ensure __set_errno is still visible on LP32. The use of the .hidden directive to avoid going via the PLT for __set_errno had the side-effect of actually making __set_errno hidden (which is odd because assembler directives don't usually affect symbols defined in a different file --- you can't even create a weak reference to a symbol that's defined in a different file). This change switches the system call stubs over to a new always-hidden __set_errno_internal and has a visible __set_errno on LP32 just for binary compatibility with old NDK apps. (cherry-pick of 7efad83d430f4d824f2aaa75edea5106f6ff8aae.) Bug: 17423135 Change-Id: I6b6d7a05dda85f923d22e5ffd169a91e23499b7b
2014-09-08 22:25:01 +00:00
call __set_errno_internal
Regenerate the system call stubs (to get x86_64). This touches the x86 stubs too because arm, x86, and x86_64 now all share the same header (at a source level), which causes a reordering of the #include lines. Change-Id: If9a1e2b2718bd41d8399fea748bce672c513ef84
2013-10-01 20:29:43 +00:00
1:
ret
Add fchmodat(AT_SYMLINK_NOFOLLOW) and fchmod O_PATH support Many libc functions have an option to not follow symbolic links. This is useful to avoid security sensitive code from inadvertantly following attacker supplied symlinks and taking inappropriate action on files it shouldn't. For example, open() has O_NOFOLLOW, chown() has lchown(), stat() has lstat(), etc. There is no such equivalent function for chmod(), such as lchmod(). To address this, POSIX introduced fchmodat(AT_SYMLINK_NOFOLLOW), which is intended to provide a way to perform a chmod operation which doesn't follow symlinks. Currently, the Linux kernel doesn't implement AT_SYMLINK_NOFOLLOW. In GLIBC, attempting to use the AT_SYMLINK_NOFOLLOW flag causes fchmodat to return ENOTSUP. Details are in "man fchmodat". Bionic currently differs from GLIBC in that AT_SYMLINK_NOFOLLOW is silently ignored and treated as if the flag wasn't present. This patch provides a userspace implementation of AT_SYMLINK_NOFOLLOW for bionic. Using open(O_PATH | O_NOFOLLOW), we can provide a way to atomically change the permissions on files without worrying about race conditions. As part of this change, we add support for fchmod on O_PATH file descriptors, because it's relatively straight forward and could be useful in the future. The basic idea behind this implementation comes from https://sourceware.org/bugzilla/show_bug.cgi?id=14578 , specifically comment #10. Change-Id: I1eba0cdb2c509d9193ceecf28f13118188a3cfa7
2015-02-01 03:57:46 +00:00
END(__fchmodat)
.hidden __fchmodat