| Date | Fri, 21 Mar 2008 15:43:54 -0700 | From | Chris Wright <> | Subject | [patch 64/76] nfsd: fix oops on access from high-numbered ports |
| |
-stable review patch. If anyone has any objections, please let us know. ---------------------
From: J. Bruce Fields <bfields@citi.umich.edu>
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 <bfields@citi.umich.edu> Cc: Lukas Hejtmanek <xhejtman@ics.muni.cz> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Chris Wright <chrisw@sous-sol.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> --- fs/nfsd/nfsfh.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/fs/nfsd/nfsfh.c +++ b/fs/nfsd/nfsfh.c @@ -231,6 +231,7 @@ fh_verify(struct svc_rqst *rqstp, struct fhp->fh_dentry = dentry; fhp->fh_export = exp; nfsd_nr_verified++; + cache_get(&exp->h); } else { /* * just rechecking permissions @@ -240,6 +241,7 @@ fh_verify(struct svc_rqst *rqstp, struct 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 @@ -251,8 +253,6 @@ fh_verify(struct svc_rqst *rqstp, struct if (error) goto out; } - cache_get(&exp->h); - error = nfsd_mode_check(rqstp, dentry->d_inode->i_mode, type); if (error) --
|