From: Kinglong Mee Date: Fri, 23 May 2014 11:57:49 +0000 (+0800) Subject: NFS4: Avoid NULL reference or double free in nfsd4_fslocs_free() X-Git-Tag: firefly_0821_release~176^2~3796^2~27 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=a1f05514b016aeaed638dbf677f443af7e7bde4f;p=firefly-linux-kernel-4.4.55.git NFS4: Avoid NULL reference or double free in nfsd4_fslocs_free() 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 Signed-off-by: J. Bruce Fields --- diff --git a/fs/nfsd/export.c b/fs/nfsd/export.c index 8513c598fabf..9a41d3ddd8df 100644 --- a/fs/nfsd/export.c +++ b/fs/nfsd/export.c @@ -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)