Please sign in to comment.
net: fib: fib6_add: fix potential NULL pointer dereference
When the kernel is compiled with CONFIG_IPV6_SUBTREES, and we return with an error in fn = fib6_add_1(), then error codes are encoded into the return pointer e.g. ERR_PTR(-ENOENT). In such an error case, we write the error code into err and jump to out, hence enter the if(err) condition. Now, if CONFIG_IPV6_SUBTREES is enabled, we check for: if (pn != fn && pn->leaf == rt) ... if (pn != fn && !pn->leaf && !(pn->fn_flags & RTN_RTINFO)) ... Since pn is NULL and fn is f.e. ERR_PTR(-ENOENT), then pn != fn evaluates to true and causes a NULL-pointer dereference on further checks on pn. Fix it, by setting both NULL in error case, so that pn != fn already evaluates to false and no further dereference takes place. This was first correctly implemented in 4a287eb ("IPv6 routing, NLM_F_* flag support: REPLACE and EXCL flags support, warn about missing CREATE flag"), but the bug got later on introduced by 188c517 ("ipv6: return errno pointers consistently for fib6_add_1()"). Signed-off-by: Daniel Borkmann <email@example.com> Cc: Lin Ming <firstname.lastname@example.org> Cc: Matti Vaittinen <email@example.com> Cc: Hannes Frederic Sowa <firstname.lastname@example.org> Acked-by: Hannes Frederic Sowa <email@example.com> Acked-by: Matti Vaittinen <firstname.lastname@example.org> Signed-off-by: David S. Miller <email@example.com>
- Loading branch information...