Testcase: #define _GNU_SOURCE #include #include int main (void) { int dfd = open ("/tmp", O_RDONLY); int fd1 = openat (dfd, "abc", O_RDONLY); int fd2 = openat (0x12345678, "/tmp/abc", O_RDONLY); int fd3 = openat (AT_FDCWD, "abc", O_RDONLY); /* This is the only one that should warn. */ int fd4 = openat (0x12345678, "abc", O_RDONLY); return 0; } --- valgrind-3.7.0/coregrind/m_syswrap/syswrap-linux.c.jj 2007-12-11 00:18:43.000000000 +0100 +++ valgrind-3.7.0/coregrind/m_syswrap/syswrap-linux.c 2008-03-03 11:35:15.000000000 +0100 @@ -2455,10 +2455,15 @@ PRE(sys_openat) int, dfd, const char *, filename, int, flags); } - if (ARG1 != VKI_AT_FDCWD && !ML_(fd_allowed)(ARG1, "openat", tid, False)) + PRE_MEM_RASCIIZ( "openat(filename)", ARG2 ); + + /* For absolute filenames, dfd is ignored. If dfd is AT_FDCWD, + filename is relative to cwd. */ + if (ML_(safe_to_deref)( (void*)ARG2, 1 ) + && *(Char *)ARG2 != '/' + && ARG1 != VKI_AT_FDCWD + && !ML_(fd_allowed)(ARG1, "openat", tid, False)) SET_STATUS_Failure( VKI_EBADF ); - else - PRE_MEM_RASCIIZ( "openat(filename)", ARG2 ); /* Handle the case where the open is of /proc/self/cmdline or /proc//cmdline, and just give it a copy of the fd for the