6.1-stable review patch. If anyone has any objections, please let me know.
------------------
From: Breno Leitao <leitao@debian.org>
[ Upstream commit 77e5eb0e192aec6710c03ca8144582fd2af36ca4 ]
pep_getsockopt() clamps the reported length to the caller's buffer with
min_t(), but then stores the value with put_user(val, (int __user *)
optval), which always writes sizeof(int) bytes. A getsockopt() call with
an optlen smaller than sizeof(int) thus reports the clamped length yet
writes a full int, one to three bytes past the user buffer.
Write the value with copy_to_user() bounded by len, so at most optlen
bytes are copied, matching the length reported back to userspace.
Fixes: 02a47617cdce ("Phonet: implement GPRS virtual interface over PEP socket")
Acked-by: Rémi Denis-Courmont <redacted>
Reviewed-by: Joe Damato <redacted>
Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Signed-off-by: Breno Leitao <leitao@debian.org>
Link: https://patch.msgid.link/20260729-getsockopt_phase4-v4-4-c44576757c17@debian.org (local)
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/phonet/pep.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/phonet/pep.c b/net/phonet/pep.c
index 0f10979598455..bbc7ad77a5d1d 100644
--- a/net/phonet/pep.c
+++ b/net/phonet/pep.c
@@ -1117,7 +1117,7 @@ static int pep_getsockopt(struct sock *sk, int level, int optname,
len = min_t(unsigned int, sizeof(int), len);
if (put_user(len, optlen))
return -EFAULT;
- if (put_user(val, (int __user *) optval))
+ if (copy_to_user(optval, &val, len))
return -EFAULT;
return 0;
}
--
2.53.0