From f4cfb18d7917ecb397b3497e931a2a23175709b7 Mon Sep 17 00:00:00 2001 From: "Volodymyr G. Lukiianyk" Date: Wed, 15 Oct 2008 22:01:15 -0700 Subject: [PATCH] uclinux: fix gzip header parsing in binfmt_flat.c There are off-by-one errors in decompress_exec() when calculating the length of optional "original file name" and "comment" fields: the "ret" index is not incremented when terminating '\0' character is reached. The check of the buffer overflow (after an "extra-field" length was taken into account) is also fixed. I've encountered this off-by-one error when tried to reuse gzip-header-parsing part of the decompress_exec() function. There was an "original file name" field in the payload (with miscalculated length) and zlib_inflate() returned Z_DATA_ERROR. But after the fix similar to this one all worked fine. Signed-off-by: Volodymyr G Lukiianyk Acked-by: Greg Ungerer Acked-by: David Howells Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/binfmt_flat.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/fs/binfmt_flat.c b/fs/binfmt_flat.c index dfc0197905ca..ccb781a6a804 100644 --- a/fs/binfmt_flat.c +++ b/fs/binfmt_flat.c @@ -229,13 +229,13 @@ static int decompress_exec( ret = 10; if (buf[3] & EXTRA_FIELD) { ret += 2 + buf[10] + (buf[11] << 8); - if (unlikely(LBUFSIZE == ret)) { + if (unlikely(LBUFSIZE <= ret)) { DBG_FLT("binfmt_flat: buffer overflow (EXTRA)?\n"); goto out_free_buf; } } if (buf[3] & ORIG_NAME) { - for (; ret < LBUFSIZE && (buf[ret] != 0); ret++) + while (ret < LBUFSIZE && buf[ret++] != 0) ; if (unlikely(LBUFSIZE == ret)) { DBG_FLT("binfmt_flat: buffer overflow (ORIG_NAME)?\n"); @@ -243,7 +243,7 @@ static int decompress_exec( } } if (buf[3] & COMMENT) { - for (; ret < LBUFSIZE && (buf[ret] != 0); ret++) + while (ret < LBUFSIZE && buf[ret++] != 0) ; if (unlikely(LBUFSIZE == ret)) { DBG_FLT("binfmt_flat: buffer overflow (COMMENT)?\n"); -- 2.30.2