--- /dev/null
+From b602345da6cbb135ba68cf042df8ec9a73da7981 Mon Sep 17 00:00:00 2001
+From: NeilBrown <neilb@suse.com>
+Date: Mon, 4 Mar 2019 14:08:22 +1100
+Subject: nfsd: fix memory corruption caused by readdir
+
+From: NeilBrown <neilb@suse.com>
+
+commit b602345da6cbb135ba68cf042df8ec9a73da7981 upstream.
+
+If the result of an NFSv3 readdir{,plus} request results in the
+"offset" on one entry having to be split across 2 pages, and is sized
+so that the next directory entry doesn't fit in the requested size,
+then memory corruption can happen.
+
+When encode_entry() is called after encoding the last entry that fits,
+it notices that ->offset and ->offset1 are set, and so stores the
+offset value in the two pages as required. It clears ->offset1 but
+*does not* clear ->offset.
+
+Normally this omission doesn't matter as encode_entry_baggage() will
+be called, and will set ->offset to a suitable value (not on a page
+boundary).
+But in the case where cd->buflen < elen and nfserr_toosmall is
+returned, ->offset is not reset.
+
+This means that nfsd3proc_readdirplus will see ->offset with a value 4
+bytes before the end of a page, and ->offset1 set to NULL.
+It will try to write 8bytes to ->offset.
+If we are lucky, the next page will be read-only, and the system will
+ BUG: unable to handle kernel paging request at...
+
+If we are unlucky, some innocent page will have the first 4 bytes
+corrupted.
+
+nfsd3proc_readdir() doesn't even check for ->offset1, it just blindly
+writes 8 bytes to the offset wherever it is.
+
+Fix this by clearing ->offset after it is used, and copying the
+->offset handling code from nfsd3_proc_readdirplus into
+nfsd3_proc_readdir.
+
+(Note that the commit hash in the Fixes tag is from the 'history'
+ tree - this bug predates git).
+
+Fixes: 0b1d57cf7654 ("[PATCH] kNFSd: Fix nfs3 dentry encoding")
+Fixes-URL: https://git.kernel.org/pub/scm/linux/kernel/git/history/history.git/commit/?id=0b1d57cf7654
+Cc: stable@vger.kernel.org (v2.6.12+)
+Signed-off-by: NeilBrown <neilb@suse.com>
+Signed-off-by: J. Bruce Fields <bfields@redhat.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ fs/nfsd/nfs3proc.c | 16 ++++++++++++++--
+ fs/nfsd/nfs3xdr.c | 1 +
+ 2 files changed, 15 insertions(+), 2 deletions(-)
+
+--- a/fs/nfsd/nfs3proc.c
++++ b/fs/nfsd/nfs3proc.c
+@@ -430,8 +430,19 @@ nfsd3_proc_readdir(struct svc_rqst *rqst
+ &resp->common, nfs3svc_encode_entry);
+ memcpy(resp->verf, argp->verf, 8);
+ resp->count = resp->buffer - argp->buffer;
+- if (resp->offset)
+- xdr_encode_hyper(resp->offset, argp->cookie);
++ if (resp->offset) {
++ loff_t offset = argp->cookie;
++
++ if (unlikely(resp->offset1)) {
++ /* we ended up with offset on a page boundary */
++ *resp->offset = htonl(offset >> 32);
++ *resp->offset1 = htonl(offset & 0xffffffff);
++ resp->offset1 = NULL;
++ } else {
++ xdr_encode_hyper(resp->offset, offset);
++ }
++ resp->offset = NULL;
++ }
+
+ RETURN_STATUS(nfserr);
+ }
+@@ -499,6 +510,7 @@ nfsd3_proc_readdirplus(struct svc_rqst *
+ } else {
+ xdr_encode_hyper(resp->offset, offset);
+ }
++ resp->offset = NULL;
+ }
+
+ RETURN_STATUS(nfserr);
+--- a/fs/nfsd/nfs3xdr.c
++++ b/fs/nfsd/nfs3xdr.c
+@@ -892,6 +892,7 @@ encode_entry(struct readdir_cd *ccd, con
+ } else {
+ xdr_encode_hyper(cd->offset, offset64);
+ }
++ cd->offset = NULL;
+ }
+
+ /*
--- /dev/null
+From dd838821f0a29781b185cd8fb8e48d5c177bd838 Mon Sep 17 00:00:00 2001
+From: Yihao Wu <wuyihao@linux.alibaba.com>
+Date: Wed, 6 Mar 2019 21:03:50 +0800
+Subject: nfsd: fix wrong check in write_v4_end_grace()
+
+From: Yihao Wu <wuyihao@linux.alibaba.com>
+
+commit dd838821f0a29781b185cd8fb8e48d5c177bd838 upstream.
+
+Commit 62a063b8e7d1 "nfsd4: fix crash on writing v4_end_grace before
+nfsd startup" is trying to fix a NULL dereference issue, but it
+mistakenly checks if the nfsd server is started. So fix it.
+
+Fixes: 62a063b8e7d1 "nfsd4: fix crash on writing v4_end_grace before nfsd startup"
+Cc: stable@vger.kernel.org
+Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
+Signed-off-by: Yihao Wu <wuyihao@linux.alibaba.com>
+Signed-off-by: J. Bruce Fields <bfields@redhat.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+
+---
+ fs/nfsd/nfsctl.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+--- a/fs/nfsd/nfsctl.c
++++ b/fs/nfsd/nfsctl.c
+@@ -1110,7 +1110,7 @@ static ssize_t write_v4_end_grace(struct
+ case 'Y':
+ case 'y':
+ case '1':
+- if (nn->nfsd_serv)
++ if (!nn->nfsd_serv)
+ return -EBUSY;
+ nfsd4_end_grace(nn);
+ break;
projects / thirdparty / kernel / stable-queue.git / commitdiff
