diff options
| author | Heiko Carstens <heiko.carstens@de.ibm.com> | 2012-02-04 10:47:10 +0100 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-02-06 15:15:20 -0800 |
| commit | 96e02d1586782eadf051fa3d6bc4132d2447ac2c (patch) | |
| tree | dd40e6302d2770d3c51cced64cfd3b8cf1355da4 /include/linux/binfmts.h | |
| parent | 23783f817bceedd6d4e549385e3f400ea64059e5 (diff) | |
| download | lwn-96e02d1586782eadf051fa3d6bc4132d2447ac2c.tar.gz lwn-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 'include/linux/binfmts.h')
| -rw-r--r-- | include/linux/binfmts.h | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/include/linux/binfmts.h b/include/linux/binfmts.h index fd88a3945aa1..0092102db2de 100644 --- a/include/linux/binfmts.h +++ b/include/linux/binfmts.h @@ -18,7 +18,7 @@ struct pt_regs; #define BINPRM_BUF_SIZE 128 #ifdef __KERNEL__ -#include <linux/list.h> +#include <linux/sched.h> #define CORENAME_MAX_SIZE 128 @@ -58,6 +58,7 @@ struct linux_binprm { unsigned interp_flags; unsigned interp_data; unsigned long loader, exec; + char tcomm[TASK_COMM_LEN]; }; #define BINPRM_FLAGS_ENFORCE_NONDUMP_BIT 0 |