* [PATCH] powerpc/mm: don't log user reads to 0xffffffff
@ 2019-12-23 7:54 Christophe Leroy
2020-01-29 5:17 ` Michael Ellerman
0 siblings, 1 reply; 2+ messages in thread
From: Christophe Leroy @ 2019-12-23 7:54 UTC (permalink / raw)
To: Benjamin Herrenschmidt, Paul Mackerras, Michael Ellerman
Cc: linuxppc-dev, linux-kernel
Running vdsotest leaves many times the following log:
[ 79.629901] vdsotest[396]: User access of kernel address (ffffffff) - exploit attempt? (uid: 0)
A pointer set to (-1) is likely a programming error similar to
a NULL pointer and is not worth logging as an exploit attempt.
Don't log user accesses to 0xffffffff.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
---
arch/powerpc/mm/fault.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
index b5047f9b5dec..d3b4d444bf3c 100644
--- a/arch/powerpc/mm/fault.c
+++ b/arch/powerpc/mm/fault.c
@@ -354,6 +354,9 @@ static void sanity_check_fault(bool is_write, bool is_user,
* Userspace trying to access kernel address, we get PROTFAULT for that.
*/
if (is_user && address >= TASK_SIZE) {
+ if ((long)address == -1)
+ return;
+
pr_crit_ratelimited("%s[%d]: User access of kernel address (%lx) - exploit attempt? (uid: %d)\n",
current->comm, current->pid, address,
from_kuid(&init_user_ns, current_uid()));
--
2.13.3
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2019-12-23 7:54 [PATCH] powerpc/mm: don't log user reads to 0xffffffff Christophe Leroy
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