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authorGeert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>2008-11-05 17:21:16 -0500
committerDavid Woodhouse <David.Woodhouse@intel.com>2008-11-05 17:22:02 -0500
commitdc8a0843a435b2c0891e7eaea64faaf1ebec9b11 (patch)
tree2646065fd3b332e51af6d2c141833e6a00a7441b /fs
parent467622ef2acb01986eab37ef96c3632b3ea35999 (diff)
[JFFS2] fix race condition in jffs2_lzo_compress()
deflate_mutex protects the globals lzo_mem and lzo_compress_buf. However, jffs2_lzo_compress() unlocks deflate_mutex _before_ it has copied out the compressed data from lzo_compress_buf. Correct this by moving the mutex unlock after the copy. In addition, document what deflate_mutex actually protects. Cc: stable@kernel.org Signed-off-by: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com> Acked-by: Richard Purdie <rpurdie@openedhand.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Diffstat (limited to 'fs')
-rw-r--r--fs/jffs2/compr_lzo.c15
1 files changed, 9 insertions, 6 deletions
diff --git a/fs/jffs2/compr_lzo.c b/fs/jffs2/compr_lzo.c
index 47b045797e42..90cb60d09787 100644
--- a/fs/jffs2/compr_lzo.c
+++ b/fs/jffs2/compr_lzo.c
@@ -19,7 +19,7 @@
19 19
20static void *lzo_mem; 20static void *lzo_mem;
21static void *lzo_compress_buf; 21static void *lzo_compress_buf;
22static DEFINE_MUTEX(deflate_mutex); 22static DEFINE_MUTEX(deflate_mutex); /* for lzo_mem and lzo_compress_buf */
23 23
24static void free_workspace(void) 24static void free_workspace(void)
25{ 25{
@@ -49,18 +49,21 @@ static int jffs2_lzo_compress(unsigned char *data_in, unsigned char *cpage_out,
49 49
50 mutex_lock(&deflate_mutex); 50 mutex_lock(&deflate_mutex);
51 ret = lzo1x_1_compress(data_in, *sourcelen, lzo_compress_buf, &compress_size, lzo_mem); 51 ret = lzo1x_1_compress(data_in, *sourcelen, lzo_compress_buf, &compress_size, lzo_mem);
52 mutex_unlock(&deflate_mutex);
53
54 if (ret != LZO_E_OK) 52 if (ret != LZO_E_OK)
55 return -1; 53 goto fail;
56 54
57 if (compress_size > *dstlen) 55 if (compress_size > *dstlen)
58 return -1; 56 goto fail;
59 57
60 memcpy(cpage_out, lzo_compress_buf, compress_size); 58 memcpy(cpage_out, lzo_compress_buf, compress_size);
61 *dstlen = compress_size; 59 mutex_unlock(&deflate_mutex);
62 60
61 *dstlen = compress_size;
63 return 0; 62 return 0;
63
64 fail:
65 mutex_unlock(&deflate_mutex);
66 return -1;
64} 67}
65 68
66static int jffs2_lzo_decompress(unsigned char *data_in, unsigned char *cpage_out, 69static int jffs2_lzo_decompress(unsigned char *data_in, unsigned char *cpage_out,