From: J. Bruce Fields Date: Fri, 14 Mar 2008 23:37:11 +0000 (-0400) Subject: nfsd: fix oops on access from high-numbered ports X-Git-Tag: v2.6.25-rc6~13 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b663c6fd98c9cf586279db03cec3257c413efd00;p=linux-2.6 nfsd: fix oops on access from high-numbered ports This bug was always here, but before my commit 6fa02839bf9412e18e77 ("recheck for secure ports in fh_verify"), it could only be triggered by failure of a kmalloc(). After that commit it could be triggered by a client making a request from a non-reserved port for access to an export marked "secure". (Exports are "secure" by default.) The result is a struct svc_export with a reference count one too low, resulting in likely oopses next time the export is accessed. The reference counting here is not straightforward; a later patch will clean up fh_verify(). Thanks to Lukas Hejtmanek for the bug report and followup. Signed-off-by: J. Bruce Fields Cc: Lukas Hejtmanek Signed-off-by: Linus Torvalds --- diff --git a/fs/nfsd/nfsfh.c b/fs/nfsd/nfsfh.c index 1eb771d79c..3e6b3f41ee 100644 --- a/fs/nfsd/nfsfh.c +++ b/fs/nfsd/nfsfh.c @@ -232,6 +232,7 @@ fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access) fhp->fh_dentry = dentry; fhp->fh_export = exp; nfsd_nr_verified++; + cache_get(&exp->h); } else { /* * just rechecking permissions @@ -241,6 +242,7 @@ fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access) dprintk("nfsd: fh_verify - just checking\n"); dentry = fhp->fh_dentry; exp = fhp->fh_export; + cache_get(&exp->h); /* * Set user creds for this exportpoint; necessary even * in the "just checking" case because this may be a @@ -252,8 +254,6 @@ fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access) if (error) goto out; } - cache_get(&exp->h); - error = nfsd_mode_check(rqstp, dentry->d_inode->i_mode, type); if (error)