From bb75611c3bd5741afda2bd797accacd2c96bec9a Mon Sep 17 00:00:00 2001 From: Kyle McMartin Date: Sat, 18 Dec 2010 10:44:57 -0500 Subject: [PATCH] fs-call-security_d_instantiate-in-d_obtain_alias (#662344) --- ...rity_d_instantiate-in-d_obtain_alias.patch | 65 +++++++++++++++++++ kernel.spec | 8 +++ 2 files changed, 73 insertions(+) create mode 100644 fs-call-security_d_instantiate-in-d_obtain_alias.patch diff --git a/fs-call-security_d_instantiate-in-d_obtain_alias.patch b/fs-call-security_d_instantiate-in-d_obtain_alias.patch new file mode 100644 index 000000000..b151c0a70 --- /dev/null +++ b/fs-call-security_d_instantiate-in-d_obtain_alias.patch @@ -0,0 +1,65 @@ +From linux-fsdevel-owner@vger.kernel.org Thu Nov 18 21:03:11 2010 +From: Josef Bacik +To: linux-fsdevel@vger.kernel.org, eparis@redhat.com, + linux-kernel@vger.kernel.org, sds@tycho.nsa.gov, + selinux@tycho.nsa.gov, bfields@fieldses.org +Subject: [PATCH] fs: call security_d_instantiate in d_obtain_alias V2 +Date: Thu, 18 Nov 2010 20:52:55 -0500 +Message-Id: <1290131575-2489-1-git-send-email-josef@redhat.com> +X-Mailing-List: linux-fsdevel@vger.kernel.org + +While trying to track down some NFS problems with BTRFS, I kept noticing I was +getting -EACCESS for no apparent reason. Eric Paris and printk() helped me +figure out that it was SELinux that was giving me grief, with the following +denial + +type=AVC msg=audit(1290013638.413:95): avc: denied { 0x800000 } for pid=1772 +comm="nfsd" name="" dev=sda1 ino=256 scontext=system_u:system_r:kernel_t:s0 +tcontext=system_u:object_r:unlabeled_t:s0 tclass=file + +Turns out this is because in d_obtain_alias if we can't find an alias we create +one and do all the normal instantiation stuff, but we don't do the +security_d_instantiate. + +Usually we are protected from getting a hashed dentry that hasn't yet run +security_d_instantiate() by the parent's i_mutex, but obviously this isn't an +option there, so in order to deal with the case that a second thread comes in +and finds our new dentry before we get to run security_d_instantiate(), we go +ahead and call it if we find a dentry already. Eric assures me that this is ok +as the code checks to see if the dentry has been initialized already so calling +security_d_instantiate() against the same dentry multiple times is ok. With +this patch I'm no longer getting errant -EACCESS values. + +Signed-off-by: Josef Bacik +--- +V1->V2: +-added second security_d_instantiate() call + + fs/dcache.c | 3 +++ + 1 files changed, 3 insertions(+), 0 deletions(-) + +diff --git a/fs/dcache.c b/fs/dcache.c +index 23702a9..119d489 100644 +--- a/fs/dcache.c ++++ b/fs/dcache.c +@@ -1201,9 +1201,12 @@ struct dentry *d_obtain_alias(struct inode *inode) + spin_unlock(&tmp->d_lock); + + spin_unlock(&dcache_lock); ++ security_d_instantiate(tmp, inode); + return tmp; + + out_iput: ++ if (res && !IS_ERR(res)) ++ security_d_instantiate(res, inode); + iput(inode); + return res; + } +-- +1.6.6.1 + +-- +To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in +the body of a message to majordomo@vger.kernel.org +More majordomo info at http://vger.kernel.org/majordomo-info.html + diff --git a/kernel.spec b/kernel.spec index 5911460f2..3733ca617 100644 --- a/kernel.spec +++ b/kernel.spec @@ -719,6 +719,8 @@ Patch12411: mm-vmstat-use-a-single-setter-function-and-callback-for-adjusting-pe # rhbz#650934 Patch12420: sched-cure-more-NO_HZ-load-average-woes.patch +Patch12421: fs-call-security_d_instantiate-in-d_obtain_alias.patch + %endif BuildRoot: %{_tmppath}/kernel-%{KVERREL}-root @@ -1329,6 +1331,9 @@ ApplyPatch mm-vmstat-use-a-single-setter-function-and-callback-for-adjusting-per # rhbz#650934 ApplyPatch sched-cure-more-NO_HZ-load-average-woes.patch +# rhbz#662344,600690 +ApplyPatch fs-call-security_d_instantiate-in-d_obtain_alias.patch + # END OF PATCH APPLICATIONS %endif @@ -1942,6 +1947,9 @@ fi # || || %changelog +* Sat Dec 18 2010 Kyle McMartin +- Fix SELinux issues with NFS/btrfs and/or xfsdump. (#662344) + * Fri Dec 17 2010 Matthew Garrett 2.6.37-0.rc6.git0.3 - efi_default_physical.patch: Revert hunk that breaks boot - linux-next-macbook-air-input.patch: Add input support for new Macbook Airs