3.13.11.3 -stable review patch. If anyone has any objections, please let me know.
------------------ From: Eric Dumazet <[email protected]> commit 404ca80eb5c2727d78cd517d12108b040c522e12 upstream. A va_list needs to be copied in case it needs to be used twice. Thanks to Hugh for debugging this issue, leading to various panics. Tested: lpq84:~# echo "|/foobar12345 %h %h %h %h %h %h %h %h %h %h %h %h %h %h %h %h %h %h %h %h" >/proc/sys/kernel/core_pattern 'produce_core' is simply : main() { *(int *)0 = 1;} lpq84:~# ./produce_core Segmentation fault (core dumped) lpq84:~# dmesg | tail -1 [ 614.352947] Core dump to |/foobar12345 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 lpq84 (null) pipe failed Notice the last argument was replaced by a NULL (we were lucky enough to not crash, but do not try this on your production machine !) After fix : lpq83:~# echo "|/foobar12345 %h %h %h %h %h %h %h %h %h %h %h %h %h %h %h %h %h %h %h %h" >/proc/sys/kernel/core_pattern lpq83:~# ./produce_core Segmentation fault lpq83:~# dmesg | tail -1 [ 740.800441] Core dump to |/foobar12345 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 lpq83 pipe failed Fixes: 5fe9d8ca21cc ("coredump: cn_vprintf() has no reason to call vsnprintf() twice") Signed-off-by: Eric Dumazet <[email protected]> Diagnosed-by: Hugh Dickins <[email protected]> Acked-by: Oleg Nesterov <[email protected]> Cc: Neil Horman <[email protected]> Cc: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]> Signed-off-by: Kamal Mostafa <[email protected]> --- fs/coredump.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/fs/coredump.c b/fs/coredump.c index bc3fbcd..fab2568 100644 --- a/fs/coredump.c +++ b/fs/coredump.c @@ -74,10 +74,15 @@ static int expand_corename(struct core_name *cn, int size) static int cn_vprintf(struct core_name *cn, const char *fmt, va_list arg) { int free, need; + va_list arg_copy; again: free = cn->size - cn->used; - need = vsnprintf(cn->corename + cn->used, free, fmt, arg); + + va_copy(arg_copy, arg); + need = vsnprintf(cn->corename + cn->used, free, fmt, arg_copy); + va_end(arg_copy); + if (need < free) { cn->used += need; return 0; -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
