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libext2fs: avoid 32-bit overflow in ext2fs_initialize with a 512M cluster size 

If the user attemps to create a 512MB cluster, we need to adjust the
defaults to avoid a 32-bit overflow of s_blocks_per_group.  Also check
to make sure that the caller of ext2fs_initialize() has not given a
value of s_clusters_per_group that would result in an overflow of
s_blocks_per_group.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: Zheng Liu <wenqing.lz@taobao.com>
debian-1.42.9
Theodore Ts'o 2013-01-14 19:29:54 -05:00
parent 86a985e749
commit dd4f565d5a
1 changed files with 12 additions and 3 deletions
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15
lib/ext2fs/initialize.c
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@ -207,6 +207,8 @@ errcode_t ext2fs_initialize(const char *name, int flags,
super->s_log_block_size;
if (bigalloc_flag) {
unsigned long long bpg;
if (param->s_blocks_per_group &&
param->s_clusters_per_group &&
((param->s_clusters_per_group * EXT2FS_CLUSTER_RATIO(fs)) !=
@ -220,12 +222,19 @@ errcode_t ext2fs_initialize(const char *name, int flags,
super->s_clusters_per_group =
param->s_blocks_per_group /
EXT2FS_CLUSTER_RATIO(fs);
else
else if (super->s_log_cluster_size + 15 < 32)
super->s_clusters_per_group = fs->blocksize * 8;
else
super->s_clusters_per_group = (fs->blocksize - 1) * 8;
if (super->s_clusters_per_group > EXT2_MAX_CLUSTERS_PER_GROUP(super))
super->s_clusters_per_group = EXT2_MAX_CLUSTERS_PER_GROUP(super);
super->s_blocks_per_group = EXT2FS_C2B(fs,
super->s_clusters_per_group);
bpg = EXT2FS_C2B(fs,
(unsigned long long) super->s_clusters_per_group);
if (bpg >= (((unsigned long long) 1) << 32)) {
retval = EXT2_ET_INVALID_ARGUMENT;
goto cleanup;
}
super->s_blocks_per_group = bpg;
} else {
set_field(s_blocks_per_group, fs->blocksize * 8);
if (super->s_blocks_per_group > EXT2_MAX_BLOCKS_PER_GROUP(super))