Commit ebfddb3d authored by Arnd Bergmann's avatar Arnd Bergmann Committed by Linus Torvalds

fscache: fix fscache_objlist_show format processing

gcc points out a minor bug in the handling of unknown cookie types,
which could result in a string overflow when the integer is copied into
a 3-byte string:

  fs/fscache/object-list.c: In function 'fscache_objlist_show':
  fs/fscache/object-list.c:265:19: error: 'sprintf' may write a terminating nul past the end of the destination [-Werror=format-overflow=]
   sprintf(_type, "%02u", cookie->def->type);
                  ^~~~~~
  fs/fscache/object-list.c:265:4: note: 'sprintf' output between 3 and 4 bytes into a destination of size 3

This is currently harmless as no code sets a type other than 0 or 1, but
it makes sense to use snprintf() here to avoid overflowing the array if
that changes.

Link: http://lkml.kernel.org/r/20170714120720.906842-22-arnd@arndb.deSigned-off-by: default avatarArnd Bergmann <arnd@arndb.de>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 8185f570
...@@ -262,7 +262,8 @@ static int fscache_objlist_show(struct seq_file *m, void *v) ...@@ -262,7 +262,8 @@ static int fscache_objlist_show(struct seq_file *m, void *v)
type = "DT"; type = "DT";
break; break;
default: default:
sprintf(_type, "%02u", cookie->def->type); snprintf(_type, sizeof(_type), "%02u",
cookie->def->type);
type = _type; type = _type;
break; break;
} }
......
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