Fix fscanf format string security bug in layout.c

An internal security audit of the flashrom project by
Carl-Daniel Hailfinger found a buffer overflow bug present in all
flashrom versions since the year 2005.
This bug was independently found and reported to flashrom.org by
Cosmin Gorgovan a few days ago. 

A buffer on the stack and a buffer on the heap are affected by the
overflow caused by an incorrect fscanf format string.
The buffer overflow can only be triggered if the optional layout feature
is used and if the user manually specifies a specially crafted layout
file on the command line. Command line parsing and flash image handling
do not trigger the buggy code path.
Most usage of flashrom does not involve layout files.

The fix in this commit (changed fscanf format string) can be applied to
layout.c of all past flashrom versions.

Corresponding to flashrom svn r1953.

Signed-off-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net>
Acked-by: Stefan Tauner <stefan.tauner@alumni.tuwien.ac.at>

1 files changed, 1 insertions, 1 deletions

diff --git a/layout.c b/layout.c
index d03945138..f71eeaa80 100644
--- a/layout.c
+++ b/layout.c
@@ -68,7 +68,7 @@ int read_romlayout(const char *name)
 			(void)fclose(romlayout);
 			return 1;
 		}
-		if (2 != fscanf(romlayout, "%s %s\n", tempstr, rom_entries[num_rom_entries].name))
+		if (2 != fscanf(romlayout, "%255s %255s\n", tempstr, rom_entries[num_rom_entries].name))
 			continue;
 #if 0
 		// fscanf does not like arbitrary comments like that :( later