On 02/27/2013 03:57 PM, Guenter Roeck wrote:
Building sctp may fail with:
In function ‘copy_from_user’,
inlined from ‘sctp_getsockopt_assoc_stats’ at
net/sctp/socket.c:5656:20:
arch/x86/include/asm/uaccess_32.h:211:26: error: call to
‘copy_from_user_overflow’ declared with attribute error: copy_from_user()
buffer size is not provably correct
if built with W=1 due to a missing parameter size validation
before the call to copy_from_user.
Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
---
v2: Fix by moving the existing parameter size validation up
in the function instead of adding an additional one.
This works too...
Acked-by: Vlad Yasevich <vyasevich@xxxxxxxxx>
net/sctp/socket.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index cedd9bf..9ef5c73 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -5653,6 +5653,9 @@ static int sctp_getsockopt_assoc_stats(struct sock *sk, int len,
if (len < sizeof(sctp_assoc_t))
return -EINVAL;
+ /* Allow the struct to grow and fill in as much as possible */
+ len = min_t(size_t, len, sizeof(sas));
+
if (copy_from_user(&sas, optval, len))
return -EFAULT;
@@ -5686,9 +5689,6 @@ static int sctp_getsockopt_assoc_stats(struct sock *sk, int len,
/* Mark beginning of a new observation period */
asoc->stats.max_obs_rto = asoc->rto_min;
- /* Allow the struct to grow and fill in as much as possible */
- len = min_t(size_t, len, sizeof(sas));
-
if (put_user(len, optlen))
return -EFAULT;
--
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