(switched to email. Please respond via emailed reply-to-all, not via the bugzilla web interface). On Wed, 19 Mar 2008 13:15:36 -0700 (PDT) bugme-daemon@xxxxxxxxxxxxxxxxxxx wrote: > http://bugzilla.kernel.org/show_bug.cgi?id=10284 > > Summary: executables with read bit 'off' cannot open /dev/stdin > Product: File System > Version: 2.5 > KernelVersion: 2.6.16.27-0.9-smp > Platform: All > OS/Version: Linux > Tree: Mainline > Status: NEW > Severity: normal > Priority: P1 > Component: devfs > AssignedTo: fs_devfs@xxxxxxxxxxxxxxxxxxxx > ReportedBy: joe@xxxxxxxxxxxx > > > Latest working kernel version: 2.6.16.27 > Earliest failing kernel version: 2.4.21 > Distribution: suse > Hardware Environment: x86_64 > Software Environment: > Problem Description: if the read bit of a binary executable is off, then open() > on /dev/stdin fails with a EACCES error. This is, umm, unexpected? > Steps to reproduce: > A short program that calls open on /dev/stdin: > > cat open_stdin.c > #include <stdio.h> > #include <stdlib.h> > #include <sys/types.h> > #include <sys/stat.h> > #include <fcntl.h> > > int main(int argc, char **argv) { > open("/dev/stdin",O_RDONLY); > return 0; > } > > tracing system calls with normal operation shows that this completes > successfully. But: > > chmod -r open_stdin > strace ./open_stdin > execve("./open_stdin", ["./open_stdin"], [/* 96 vars */]) = 0 > brk(0) = 0x501000 > mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = > 0x2b25d01b6000 > uname({sys="Linux", node="lush", ...}) = 0 > access("/etc/ld.so.preload", R_OK) = -1 ENOENT (No such file or directory) > ... (open's on .so's deleted) ... > open("/etc/ld.so.cache", O_RDONLY) = 3 > fstat(3, {st_mode=S_IFREG|0644, st_size=158841, ...}) = 0 > mmap(NULL, 158841, PROT_READ, MAP_PRIVATE, 3, 0) = 0x2b25d01b7000 > close(3) = 0 > open("/lib64/libc.so.6", O_RDONLY) = 3 > read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0P\322\1\0"..., 832) = > 832 > fstat(3, {st_mode=S_IFREG|0755, st_size=1475924, ...}) = 0 > mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = > 0x2b25d01de000 > mmap(NULL, 2289896, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = > 0x2b25d02b8000 > madvise(0x2b25d02b8000, 2289896, MADV_SEQUENTIAL|0x1) = 0 > mprotect(0x2b25d03df000, 1044480, PROT_NONE) = 0 > mmap(0x2b25d04de000, 20480, PROT_READ|PROT_WRITE, > MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x126000) = 0x2b25d04de000 > mmap(0x2b25d04e3000, 16616, PROT_READ|PROT_WRITE, > MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x2b25d04e3000close(3) > = 0 > mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = > 0x2b25d04e8000 > arch_prctl(ARCH_SET_FS, 0x2b25d04e86d0) = 0 > mprotect(0x2b25d04de000, 12288, PROT_READ) = 0 > munmap(0x2b25d01b7000, 158841) = 0 > open("/dev/stdin", O_RDONLY) = -1 EACCES (Permission denied) > > > The last line shows a Permission denied error on opening /dev/stdin. If a > normal filesystem (i.e. not-/dev/) filename is used, the open works normally. > > I have reproduced this on 2.4 and 2.6 kernels > Just a guess here: is an error flag from attempting to read the binary not > getting cleared and is being reported when trying to open stdin? > -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
