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NFS4: Avoid NULL reference or double free in nfsd4_fslocs_free()

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If fsloc_parse() failed at kzalloc(), fs/nfsd/export.c
 411
 412         fsloc->locations = kzalloc(fsloc->locations_count
 413                         * sizeof(struct nfsd4_fs_location), GFP_KERNEL);
 414         if (!fsloc->locations)
 415                 return -ENOMEM;

svc_export_parse() will call nfsd4_fslocs_free() with fsloc->locations = NULL,
so that, "kfree(fsloc->locations[i].path);" will cause a crash.

If fsloc_parse() failed after that, fsloc_parse() will call nfsd4_fslocs_free(),
and svc_export_parse() will call it again, so that, a double free is caused.

This patch checks the fsloc->locations, and set to NULL after it be freed.

Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
This commit is contained in:
Kinglong Mee 2014-05-23 19:57:49 +08:00 committed by J. Bruce Fields
parent a5cddc885b
commit a1f05514b0
1 changed files with 9 additions and 3 deletions
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12
fs/nfsd/export.c
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@ -295,13 +295,19 @@ svc_expkey_update(struct cache_detail *cd, struct svc_expkey *new,
static void nfsd4_fslocs_free(struct nfsd4_fs_locations *fsloc)
{
struct nfsd4_fs_location *locations = fsloc->locations;
int i;
if (!locations)
return;
for (i = 0; i < fsloc->locations_count; i++) {
kfree(fsloc->locations[i].path);
kfree(fsloc->locations[i].hosts);
kfree(locations[i].path);
kfree(locations[i].hosts);
}
kfree(fsloc->locations);
kfree(locations);
fsloc->locations = NULL;
}
static void svc_export_put(struct kref *ref)