exec: increase BINPRM_BUF_SIZE to 256

Large enterprise clients often run applications out of networked file
systems where the IT mandated layout of project volumes can end up
leading to paths that are longer than 128 characters.  Bumping this up
to the next order of two solves this problem in all but the most
egregious case while still fitting into a 512b slab.

[oleg@redhat.com: update comment, per Kees]
Link: http://lkml.kernel.org/r/20181112160956.GA28472@redhat.com
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reported-by: Ben Woodard <woodard@redhat.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/exec.c b/fs/exec.c
index bf0ace3841ad6efc27ab37b88a32d5a367aad159..2e0033348d8e10c02a5c3928caec876798edb1fd 100644 (file)
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1563,7 +1563,7 @@ static void bprm_fill_uid(struct linux_binprm *bprm)
 
 /*
  * Fill the binprm structure from the inode.
- * Check permissions, then read the first 128 (BINPRM_BUF_SIZE) bytes
+ * Check permissions, then read the first BINPRM_BUF_SIZE bytes
  *
  * This may be called multiple times for binary chains (scripts for example).
  */

diff --git a/include/uapi/linux/binfmts.h b/include/uapi/linux/binfmts.h
index 4abad03a88530574a5b07760b4e194d90eae54b4..689025d9c185b06abe50e36161c88ca263bba7cf 100644 (file)
--- a/include/uapi/linux/binfmts.h
+++ b/include/uapi/linux/binfmts.h
@@ -16,6 +16,6 @@ struct pt_regs;
 #define MAX_ARG_STRINGS 0x7FFFFFFF
 
 /* sizeof(linux_binprm->buf) */
-#define BINPRM_BUF_SIZE 128
+#define BINPRM_BUF_SIZE 256
 
 #endif /* _UAPI_LINUX_BINFMTS_H */