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author | Heiko Carstens <heiko.carstens@de.ibm.com> | 2012-02-04 10:47:10 +0100 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-02-06 15:15:20 -0800 |
commit | 96e02d1586782eadf051fa3d6bc4132d2447ac2c (patch) | |
tree | dd40e6302d2770d3c51cced64cfd3b8cf1355da4 /fs/logfs/readwrite.c | |
parent | 23783f817bceedd6d4e549385e3f400ea64059e5 (diff) | |
download | linux-96e02d1586782eadf051fa3d6bc4132d2447ac2c.tar.gz linux-96e02d1586782eadf051fa3d6bc4132d2447ac2c.tar.bz2 linux-96e02d1586782eadf051fa3d6bc4132d2447ac2c.zip |
exec: fix use-after-free bug in setup_new_exec()
Setting the task name is done within setup_new_exec() by accessing
bprm->filename. However this happens after flush_old_exec().
This may result in a use after free bug, flush_old_exec() may
"complete" vfork_done, which will wake up the parent which in turn
may free the passed in filename.
To fix this add a new tcomm field in struct linux_binprm which
contains the now early generated task name until it is used.
Fixes this bug on s390:
Unable to handle kernel pointer dereference at virtual kernel address 0000000039768000
Process kworker/u:3 (pid: 245, task: 000000003a3dc840, ksp: 0000000039453818)
Krnl PSW : 0704000180000000 0000000000282e94 (setup_new_exec+0xa0/0x374)
Call Trace:
([<0000000000282e2c>] setup_new_exec+0x38/0x374)
[<00000000002dd12e>] load_elf_binary+0x402/0x1bf4
[<0000000000280a42>] search_binary_handler+0x38e/0x5bc
[<0000000000282b6c>] do_execve_common+0x410/0x514
[<0000000000282cb6>] do_execve+0x46/0x58
[<00000000005bce58>] kernel_execve+0x28/0x70
[<000000000014ba2e>] ____call_usermodehelper+0x102/0x140
[<00000000005bc8da>] kernel_thread_starter+0x6/0xc
[<00000000005bc8d4>] kernel_thread_starter+0x0/0xc
Last Breaking-Event-Address:
[<00000000002830f0>] setup_new_exec+0x2fc/0x374
Kernel panic - not syncing: Fatal exception: panic_on_oops
Reported-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/logfs/readwrite.c')
0 files changed, 0 insertions, 0 deletions