Messages in this thread Patch in this message | | | Subject | [PATCH 3/3] lzma/gzip: Fix potential oops when input data is truncated | From | Phillip Lougher <> | Date | Tue, 23 Jun 2009 06:06:19 +0100 |
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If the lzma/gzip decompressors are called with insufficient input data (len > 0 & fill = NULL), they will attempt to call the fill function to obtain more data, leading to a kernel oops.
Signed-off-by: Phillip Lougher <phillip@lougher.demon.co.uk> --- lib/decompress_inflate.c | 8 ++++++++ lib/decompress_unlzma.c | 10 +++++++++- 2 files changed, 17 insertions(+), 1 deletions(-)
diff --git a/lib/decompress_inflate.c b/lib/decompress_inflate.c index bfe605a..aeae9ba 100644 --- a/lib/decompress_inflate.c +++ b/lib/decompress_inflate.c @@ -27,6 +27,11 @@ #define GZIP_IOBUF_SIZE (16*1024) +static int nofill(void *buffer, unsigned int len) +{ + return -1; +} + /* Included from initramfs et al code */ STATIC int INIT gunzip(unsigned char *buf, int len, int(*fill)(void*, unsigned int), @@ -76,6 +81,9 @@ STATIC int INIT gunzip(unsigned char *buf, int len, goto gunzip_nomem4; } + if (!fill) + fill = nofill; + if (len == 0) len = fill(zbuf, GZIP_IOBUF_SIZE); diff --git a/lib/decompress_unlzma.c b/lib/decompress_unlzma.c index d3f9468..08776f3 100644 --- a/lib/decompress_unlzma.c +++ b/lib/decompress_unlzma.c @@ -82,6 +82,11 @@ struct rc { #define RC_MODEL_TOTAL_BITS 11 +static int nofill(void *buffer, unsigned int len) +{ + return -1; +} + /* Called twice: once at startup and once in rc_normalize() */ static void INIT rc_read(struct rc *rc) { @@ -97,7 +102,10 @@ static inline void INIT rc_init(struct rc *rc, int (*fill)(void*, unsigned int), char *buffer, int buffer_size) { - rc->fill = fill; + if (fill) + rc->fill = fill; + else + rc->fill = nofill; rc->buffer = (uint8_t *)buffer; rc->buffer_size = buffer_size; rc->buffer_end = rc->buffer + rc->buffer_size; -- 1.6.1.2
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