a595a81df6
commit ae3419fbac845b4d3f3a9fae4cc80c68d82cdf6e upstream.
Commit 226fae124b2d ("vc_screen: move load of struct vc_data pointer in
vcs_read() to avoid UAF") moved the call to vcs_vc() into the loop.
While doing this it also moved the unconditional assignment of
ret = -ENXIO;
This unconditional assignment was valid outside the loop but within it
it clobbers the actual value of ret.
To avoid this only assign "ret = -ENXIO" when actually needed.
[ Also, the 'goto unlock_out" needs to be just a "break", so that it
does the right thing when it exits on later iterations when partial
success has happened - Linus ]
Reported-by: Storm Dragon <stormdragon2976@gmail.com>
Link: https://lore.kernel.org/lkml/Y%2FKS6vdql2pIsCiI@hotmail.com/
Fixes: 226fae124b2d ("vc_screen: move load of struct vc_data pointer in vcs_read() to avoid UAF")
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Link: https://lore.kernel.org/lkml/64981d94-d00c-4b31-9063-43ad0a384bde@t-8ch.de/
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>