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prctl: Use access_ok instead of TASK_SIZE in prctl_set_mm

PATCH New Cyrill Gorcunov 1 participant 1 message Sep 25, 2012

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Cyrill Gorcunov

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PATCH 1/1 prctl: Use access_ok instead of TASK_SIZE in prctl_set_mm

Eric pointed that better to use access_ok instead of TASK_SIZE for testing if address is allowed for use.

Reported-by "Eric W. Biederman" <[email protected]>
Signed-off-by Cyrill Gorcunov <[email protected]>
CC Mark Salter <[email protected]>
CC Kees Cook <[email protected]>
CC Andrew Morton <[email protected]>
CC Pavel Emelyanov <[email protected]>
---
 kernel/sys.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
kernel/sys.c +1 -1
Index: linux-2.6.git/kernel/sys.c
===================================================================
@@ -1865,7 +1865,7 @@ static int prctl_set_mm(int opt, unsigne
 	if (opt == PR_SET_MM_EXE_FILE)
 		return prctl_set_mm_exe_file(mm, (unsigned int)addr);
 
-	if (addr >= TASK_SIZE || addr < mmap_min_addr)
+	if (!access_ok(VERIFY_READ, addr, sizeof(addr)) || addr < mmap_min_addr)
 		return -EINVAL;
 
 	error = -EINVAL;