path: root/include
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authorHeiko Carstens <heiko.carstens@de.ibm.com>2012-02-04 10:47:10 +0100
committerLinus Torvalds <torvalds@linux-foundation.org>2012-02-06 15:15:20 -0800
commit96e02d1586782eadf051fa3d6bc4132d2447ac2c (patch)
treedd40e6302d2770d3c51cced64cfd3b8cf1355da4 /include
parent23783f817bceedd6d4e549385e3f400ea64059e5 (diff)
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')
1 files changed, 2 insertions, 1 deletions
diff --git a/include/linux/binfmts.h b/include/linux/binfmts.h
index fd88a3945aa..0092102db2d 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>
@@ -58,6 +58,7 @@ struct linux_binprm {
unsigned interp_flags;
unsigned interp_data;
unsigned long loader, exec;
+ char tcomm[TASK_COMM_LEN];