Commit 6fc367bf authored by Helge Deller's avatar Helge Deller Committed by John Johansen
Browse files

apparmor: Fix & Optimize table creation from possibly unaligned memory 



Source blob may come from userspace and might be unaligned.
Try to optize the copying process by avoiding unaligned memory accesses.

- Added Fixes tag
- Added "Fix &" to description as this doesn't just optimize but fixes
        a potential unaligned memory access
Fixes: e6e8bf41 ("apparmor: fix restricted endian type warnings for dfa unpack")
Signed-off-by: default avatarHelge Deller <deller@gmx.de>
[jj: remove duplicate word "convert" in comment trigger checkpatch warning]
Signed-off-by: default avatarJohn Johansen <john.johansen@canonical.com>
parent 64802f73

security/apparmor/include/match.h

+7 −5
Original line number Diff line number Diff line
@@ -104,15 +104,17 @@ struct aa_dfa { 
	struct table_header *tables[YYTD_ID_TSIZE];

};



#define byte_to_byte(X) (X)



#define UNPACK_ARRAY(TABLE, BLOB, LEN, TTYPE, BTYPE, NTOHX)	\

	do { \

		typeof(LEN) __i; \

		TTYPE *__t = (TTYPE *) TABLE; \

		BTYPE *__b = (BTYPE *) BLOB; \

		BUILD_BUG_ON(sizeof(TTYPE) != sizeof(BTYPE)); \

		if (IS_ENABLED(CONFIG_CPU_BIG_ENDIAN)) \

			memcpy(__t, __b, (LEN) * sizeof(BTYPE)); \

		else /* copy & convert from big-endian */ \

			for (__i = 0; __i < LEN; __i++) { \

			__t[__i] = NTOHX(__b[__i]); \

				__t[__i] = NTOHX(&__b[__i]); \

			} \

	} while (0)

security/apparmor/match.c

+3 −4
Original line number Diff line number Diff line
@@ -67,14 +67,13 @@ static struct table_header *unpack_table(char *blob, size_t bsize) 
		table->td_flags = th.td_flags;

		table->td_lolen = th.td_lolen;

		if (th.td_flags == YYTD_DATA8)

			UNPACK_ARRAY(table->td_data, blob, th.td_lolen,

				     u8, u8, byte_to_byte);

			memcpy(table->td_data, blob, th.td_lolen);

		else if (th.td_flags == YYTD_DATA16)

			UNPACK_ARRAY(table->td_data, blob, th.td_lolen,

				     u16, __be16, be16_to_cpu);

				     u16, __be16, get_unaligned_be16);

		else if (th.td_flags == YYTD_DATA32)

			UNPACK_ARRAY(table->td_data, blob, th.td_lolen,

				     u32, __be32, be32_to_cpu);

				     u32, __be32, get_unaligned_be32);

		else

			goto fail;

		/* if table was vmalloced make sure the page tables are synced