Commit 0a06ea87185531705e4417e3a051f81b64f210c1
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[WIRELESS] WEXT: Fix userspace corruption on 64-bit.
On 64-bit systems sizeof(struct ifreq) is 8 bytes larger than sizeof(struct iwreq). For GET calls, the wireless extension code copies back into userspace using sizeof(struct ifreq) but userspace and elsewhere only allocates a "struct iwreq". Thus, this copy writes past the end of the iwreq object and corrupts whatever sits after it in memory. Fix the copy_to_user() length. This particularly hurts the compat case because the wireless compat code uses compat_alloc_userspace() and right after this allocated buffer is the current bottom of the user stack, and that's what gets overwritten by the copy_to_user() call. Signed-off-by: David S. Miller <davem@davemloft.net>
Showing 1 changed file with 1 additions and 1 deletions Side-by-side Diff
net/wireless/wext.c
... | ... | @@ -1094,7 +1094,7 @@ |
1094 | 1094 | rtnl_lock(); |
1095 | 1095 | ret = wireless_process_ioctl(net, ifr, cmd); |
1096 | 1096 | rtnl_unlock(); |
1097 | - if (IW_IS_GET(cmd) && copy_to_user(arg, ifr, sizeof(struct ifreq))) | |
1097 | + if (IW_IS_GET(cmd) && copy_to_user(arg, ifr, sizeof(struct iwreq))) | |
1098 | 1098 | return -EFAULT; |
1099 | 1099 | return ret; |
1100 | 1100 | } |