From: Heinrich Schuchardt <xypron.glpk@gmx.de>
Date: Sun, 19 Nov 2017 22:49:21 +0000 (+0100)
Subject: fs: avoid possible NULL dereference in fs_devread
X-Git-Tag: v2018.01-rc1~35
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=24f48416dfe1d827dcf759d6cd0e7a8e5c67e321;p=platform%2Fkernel%2Fu-boot.git

fs: avoid possible NULL dereference in fs_devread

It is unwise to first dereference a variable
and then to check if it was NULL.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Reviewed-by: Marek Behun <marek.behun@nic.cz>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
---

diff --git a/fs/fs_internal.c b/fs/fs_internal.c
index 58b4410..5cdd272 100644
--- a/fs/fs_internal.c
+++ b/fs/fs_internal.c
@@ -15,12 +15,13 @@ int fs_devread(struct blk_desc *blk, disk_partition_t *partition,
 	       lbaint_t sector, int byte_offset, int byte_len, char *buf)
 {
 	unsigned block_len;
-	int log2blksz = blk->log2blksz;
+	int log2blksz;
 	ALLOC_CACHE_ALIGN_BUFFER(char, sec_buf, (blk ? blk->blksz : 0));
 	if (blk == NULL) {
 		printf("** Invalid Block Device Descriptor (NULL)\n");
 		return 0;
 	}
+	log2blksz = blk->log2blksz;
 
 	/* Check partition boundaries */
 	if ((sector + ((byte_offset + byte_len - 1) >> log2blksz))