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CVE-2015-2925 Don't allow bind mount escape (rhbz 1209367 1209373) 

Also fixup some patch stuff from the 4.2 rebase
This commit is contained in:
Josh Boyer 2015-10-01 20:44:18 -04:00
parent 774ec9b607
commit a95bfb8427
4 changed files with 186 additions and 215 deletions
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65
dcache-Handle-escaped-paths-in-prepend_path.patch Normal file
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@ -0,0 +1,65 @@
From c0ea161a6e7158281f64bc6d41126da43cb08f14 Mon Sep 17 00:00:00 2001
From: "Eric W. Biederman" <ebiederm@xmission.com>
Date: Sat, 15 Aug 2015 13:36:12 -0500
Subject: [PATCH 1/2] dcache: Handle escaped paths in prepend_path
commit cde93be45a8a90d8c264c776fab63487b5038a65 upstream.
A rename can result in a dentry that by walking up d_parent
will never reach it's mnt_root. For lack of a better term
I call this an escaped path.
prepend_path is called by four different functions __d_path,
d_absolute_path, d_path, and getcwd.
__d_path only wants to see paths are connected to the root it passes
in. So __d_path needs prepend_path to return an error.
d_absolute_path similarly wants to see paths that are connected to
some root. Escaped paths are not connected to any mnt_root so
d_absolute_path needs prepend_path to return an error greater
than 1. So escaped paths will be treated like paths on lazily
unmounted mounts.
getcwd needs to prepend "(unreachable)" so getcwd also needs
prepend_path to return an error.
d_path is the interesting hold out. d_path just wants to print
something, and does not care about the weird cases. Which raises
the question what should be printed?
Given that <escaped_path>/<anything> should result in -ENOENT I
believe it is desirable for escaped paths to be printed as empty
paths. As there are not really any meaninful path components when
considered from the perspective of a mount tree.
So tweak prepend_path to return an empty path with an new error
code of 3 when it encounters an escaped path.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
fs/dcache.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/fs/dcache.c b/fs/dcache.c
index 9b5fe503f6cb..e3b44ca75a1b 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -2926,6 +2926,13 @@ restart:
if (dentry == vfsmnt->mnt_root || IS_ROOT(dentry)) {
struct mount *parent = ACCESS_ONCE(mnt->mnt_parent);
+ /* Escaped? */
+ if (dentry != vfsmnt->mnt_root) {
+ bptr = *buffer;
+ blen = *buflen;
+ error = 3;
+ break;
+ }
/* Global root? */
if (mnt != parent) {
dentry = ACCESS_ONCE(mnt->mnt_mountpoint);
--
2.4.3

23
kernel.spec
View File

@ -610,9 +610,6 @@ Patch509: ideapad-laptop-Add-Lenovo-Yoga-3-14-to-no_hw_rfkill-.patch
#rhbz 1253789
Patch511: iSCSI-let-session-recovery_tmo-sysfs-writes-persist.patch
#rhbz 1256281
Patch26265: mmc-sdhci-fix-dma-memory-leak-in-sdhci_pre_req.patch
#rhbz 1257534
Patch515: nv46-Change-mc-subdev-oclass-from-nv44-to-nv4c.patch
@ -632,6 +629,10 @@ Patch526: 0001-x86-cpu-cacheinfo-Fix-teardown-path.patch
#CVE-2015-5257 rhbz 1265607 1265612
Patch527: USB-whiteheat-fix-potential-null-deref-at-probe.patch
#CVE-2015-2925 rhbz 1209367 1209373
Patch528: dcache-Handle-escaped-paths-in-prepend_path.patch
Patch529: vfs-Test-for-and-handle-paths-that-are-unreachable-f.patch
# END OF PATCH DEFINITIONS
%endif
@ -1359,12 +1360,6 @@ ApplyPatch ideapad-laptop-Add-Lenovo-Yoga-3-14-to-no_hw_rfkill-.patch
#rhbz 1253789
ApplyPatch iSCSI-let-session-recovery_tmo-sysfs-writes-persist.patch
#rhbz 1250717
ApplyPatch ext4-dont-manipulate-recovery-flag-when-freezing.patch
#rhbz 1256281
ApplyPatch mmc-sdhci-fix-dma-memory-leak-in-sdhci_pre_req.patch
#rhbz 1257534
ApplyPatch nv46-Change-mc-subdev-oclass-from-nv44-to-nv4c.patch
@ -1372,9 +1367,6 @@ ApplyPatch nv46-Change-mc-subdev-oclass-from-nv44-to-nv4c.patch
ApplyPatch vmwgfx-Rework-device-initialization.patch
ApplyPatch drm-vmwgfx-Allow-dropped-masters-render-node-like-ac.patch
#rhbz 1259231
ApplyPatch make-flush-workqueue-available-to-non-GPL-modules.patch
#rhbz 1237136
ApplyPatch block-blkg_destroy_all-should-clear-q-root_blkg-and-.patch
@ -1389,6 +1381,10 @@ ApplyPatch USB-whiteheat-fix-potential-null-deref-at-probe.patch
ApplyPatch regulator-axp20x-module-alias.patch
#CVE-2015-2925 rhbz 1209367 1209373
ApplyPatch dcache-Handle-escaped-paths-in-prepend_path.patch
ApplyPatch vfs-Test-for-and-handle-paths-that-are-unreachable-f.patch
# END OF PATCH APPLICATIONS
%endif
@ -2239,6 +2235,9 @@ fi
#
#
%changelog
* Thu Oct 01 2015 Josh Boyer <jwboyer@fedoraproject.org>
- CVE-2015-2925 Don't allow bind mount escape (rhbz 1209367 1209373)
* Tue Sep 29 2015 Justin M. Forbes <jforbes@fedoraproject.org>
- - Linux v4.2.2

203
mmc-sdhci-fix-dma-memory-leak-in-sdhci_pre_req.patch
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@ -1,203 +0,0 @@
From: Haibo Chen <haibo.chen@freescale.com>
Date: Tue, 25 Aug 2015 10:02:11 +0800
Subject: [PATCH] mmc: sdhci: fix dma memory leak in sdhci_pre_req()
Currently one mrq->data maybe execute dma_map_sg() twice
when mmc subsystem prepare over one new request, and the
following log show up:
sdhci[sdhci_pre_dma_transfer] invalid cookie: 24, next-cookie 25
In this condition, mrq->date map a dma-memory(1) in sdhci_pre_req
for the first time, and map another dma-memory(2) in sdhci_prepare_data
for the second time. But driver only unmap the dma-memory(2), and
dma-memory(1) never unmapped, which cause the dma memory leak issue.
This patch use another method to map the dma memory for the mrq->data
which can fix this dma memory leak issue.
Fixes: commit 348487cb28e66b0 ("mmc: sdhci: use pipeline mmc requests to improve performance")
Cc: stable@vger.kernel.org # 4.0+
Reported-and-tested-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Haibo Chen <haibo.chen@freescale.com>
---
drivers/mmc/host/sdhci.c | 67 ++++++++++++++++++------------------------------
drivers/mmc/host/sdhci.h | 8 +++---
2 files changed, 29 insertions(+), 46 deletions(-)
diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 1dbe932..ea10ebc 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -54,8 +54,7 @@ static void sdhci_finish_command(struct sdhci_host *);
static int sdhci_execute_tuning(struct mmc_host *mmc, u32 opcode);
static void sdhci_enable_preset_value(struct sdhci_host *host, bool enable);
static int sdhci_pre_dma_transfer(struct sdhci_host *host,
- struct mmc_data *data,
- struct sdhci_host_next *next);
+ struct mmc_data *data);
static int sdhci_do_get_cd(struct sdhci_host *host);
#ifdef CONFIG_PM
@@ -496,7 +495,7 @@ static int sdhci_adma_table_pre(struct sdhci_host *host,
goto fail;
BUG_ON(host->align_addr & host->align_mask);
- host->sg_count = sdhci_pre_dma_transfer(host, data, NULL);
+ host->sg_count = sdhci_pre_dma_transfer(host, data);
if (host->sg_count < 0)
goto unmap_align;
@@ -635,9 +634,11 @@ static void sdhci_adma_table_post(struct sdhci_host *host,
}
}
- if (!data->host_cookie)
+ if (data->host_cookie == COOKIE_MAPPED) {
dma_unmap_sg(mmc_dev(host->mmc), data->sg,
data->sg_len, direction);
+ data->host_cookie = COOKIE_UNMAPPED;
+ }
}
static u8 sdhci_calc_timeout(struct sdhci_host *host, struct mmc_command *cmd)
@@ -833,7 +834,7 @@ static void sdhci_prepare_data(struct sdhci_host *host, struct mmc_command *cmd)
} else {
int sg_cnt;
- sg_cnt = sdhci_pre_dma_transfer(host, data, NULL);
+ sg_cnt = sdhci_pre_dma_transfer(host, data);
if (sg_cnt <= 0) {
/*
* This only happens when someone fed
@@ -949,11 +950,13 @@ static void sdhci_finish_data(struct sdhci_host *host)
if (host->flags & SDHCI_USE_ADMA)
sdhci_adma_table_post(host, data);
else {
- if (!data->host_cookie)
+ if (data->host_cookie == COOKIE_MAPPED) {
dma_unmap_sg(mmc_dev(host->mmc),
data->sg, data->sg_len,
(data->flags & MMC_DATA_READ) ?
DMA_FROM_DEVICE : DMA_TO_DEVICE);
+ data->host_cookie = COOKIE_UNMAPPED;
+ }
}
}
@@ -2097,49 +2100,36 @@ static void sdhci_post_req(struct mmc_host *mmc, struct mmc_request *mrq,
struct mmc_data *data = mrq->data;
if (host->flags & SDHCI_REQ_USE_DMA) {
- if (data->host_cookie)
+ if (data->host_cookie == COOKIE_GIVEN ||
+ data->host_cookie == COOKIE_MAPPED)
dma_unmap_sg(mmc_dev(host->mmc), data->sg, data->sg_len,
data->flags & MMC_DATA_WRITE ?
DMA_TO_DEVICE : DMA_FROM_DEVICE);
- mrq->data->host_cookie = 0;
+ data->host_cookie = COOKIE_UNMAPPED;
}
}
static int sdhci_pre_dma_transfer(struct sdhci_host *host,
- struct mmc_data *data,
- struct sdhci_host_next *next)
+ struct mmc_data *data)
{
int sg_count;
- if (!next && data->host_cookie &&
- data->host_cookie != host->next_data.cookie) {
- pr_debug(DRIVER_NAME "[%s] invalid cookie: %d, next-cookie %d\n",
- __func__, data->host_cookie, host->next_data.cookie);
- data->host_cookie = 0;
+ if (data->host_cookie == COOKIE_MAPPED) {
+ data->host_cookie = COOKIE_GIVEN;
+ return data->sg_count;
}
- /* Check if next job is already prepared */
- if (next ||
- (!next && data->host_cookie != host->next_data.cookie)) {
- sg_count = dma_map_sg(mmc_dev(host->mmc), data->sg,
- data->sg_len,
- data->flags & MMC_DATA_WRITE ?
- DMA_TO_DEVICE : DMA_FROM_DEVICE);
-
- } else {
- sg_count = host->next_data.sg_count;
- host->next_data.sg_count = 0;
- }
+ WARN_ON(data->host_cookie == COOKIE_GIVEN);
+ sg_count = dma_map_sg(mmc_dev(host->mmc), data->sg, data->sg_len,
+ data->flags & MMC_DATA_WRITE ?
+ DMA_TO_DEVICE : DMA_FROM_DEVICE);
if (sg_count == 0)
- return -EINVAL;
+ return -ENOSPC;
- if (next) {
- next->sg_count = sg_count;
- data->host_cookie = ++next->cookie < 0 ? 1 : next->cookie;
- } else
- host->sg_count = sg_count;
+ data->sg_count = sg_count;
+ data->host_cookie = COOKIE_MAPPED;
return sg_count;
}
@@ -2149,16 +2139,10 @@ static void sdhci_pre_req(struct mmc_host *mmc, struct mmc_request *mrq,
{
struct sdhci_host *host = mmc_priv(mmc);
- if (mrq->data->host_cookie) {
- mrq->data->host_cookie = 0;
- return;
- }
+ mrq->data->host_cookie = COOKIE_UNMAPPED;
if (host->flags & SDHCI_REQ_USE_DMA)
- if (sdhci_pre_dma_transfer(host,
- mrq->data,
- &host->next_data) < 0)
- mrq->data->host_cookie = 0;
+ sdhci_pre_dma_transfer(host, mrq->data);
}
static void sdhci_card_event(struct mmc_host *mmc)
@@ -3030,7 +3014,6 @@ int sdhci_add_host(struct sdhci_host *host)
host->max_clk = host->ops->get_max_clock(host);
}
- host->next_data.cookie = 1;
/*
* In case of Host Controller v3.00, find out whether clock
* multiplier is supported.
diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
index 5521d29..a9512a4 100644
--- a/drivers/mmc/host/sdhci.h
+++ b/drivers/mmc/host/sdhci.h
@@ -309,9 +309,10 @@ struct sdhci_adma2_64_desc {
*/
#define SDHCI_MAX_SEGS 128
-struct sdhci_host_next {
- unsigned int sg_count;
- s32 cookie;
+enum sdhci_cookie {
+ COOKIE_UNMAPPED,
+ COOKIE_MAPPED,
+ COOKIE_GIVEN,
};
struct sdhci_host {
@@ -503,7 +504,6 @@ struct sdhci_host {
unsigned int tuning_mode; /* Re-tuning mode supported by host */
#define SDHCI_TUNING_MODE_1 0
- struct sdhci_host_next next_data;
unsigned long private[0] ____cacheline_aligned;
};

110
vfs-Test-for-and-handle-paths-that-are-unreachable-f.patch Normal file
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@ -0,0 +1,110 @@
From 14588dfe2e411056df5ba85ef88ad51730a2fa0a Mon Sep 17 00:00:00 2001
From: "Eric W. Biederman" <ebiederm@xmission.com>
Date: Sat, 15 Aug 2015 20:27:13 -0500
Subject: [PATCH 2/2] vfs: Test for and handle paths that are unreachable from
their mnt_root
commit 397d425dc26da728396e66d392d5dcb8dac30c37 upstream.
In rare cases a directory can be renamed out from under a bind mount.
In those cases without special handling it becomes possible to walk up
the directory tree to the root dentry of the filesystem and down
from the root dentry to every other file or directory on the filesystem.
Like division by zero .. from an unconnected path can not be given
a useful semantic as there is no predicting at which path component
the code will realize it is unconnected. We certainly can not match
the current behavior as the current behavior is a security hole.
Therefore when encounting .. when following an unconnected path
return -ENOENT.
- Add a function path_connected to verify path->dentry is reachable
from path->mnt.mnt_root. AKA to validate that rename did not do
something nasty to the bind mount.
To avoid races path_connected must be called after following a path
component to it's next path component.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
fs/namei.c | 27 +++++++++++++++++++++++++--
1 file changed, 25 insertions(+), 2 deletions(-)
diff --git a/fs/namei.c b/fs/namei.c
index 1c2105ed20c5..29b927938b8c 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -560,6 +560,24 @@ static int __nd_alloc_stack(struct nameidata *nd)
return 0;
}
+/**
+ * path_connected - Verify that a path->dentry is below path->mnt.mnt_root
+ * @path: nameidate to verify
+ *
+ * Rename can sometimes move a file or directory outside of a bind
+ * mount, path_connected allows those cases to be detected.
+ */
+static bool path_connected(const struct path *path)
+{
+ struct vfsmount *mnt = path->mnt;
+
+ /* Only bind mounts can have disconnected paths */
+ if (mnt->mnt_root == mnt->mnt_sb->s_root)
+ return true;
+
+ return is_subdir(path->dentry, mnt->mnt_root);
+}
+
static inline int nd_alloc_stack(struct nameidata *nd)
{
if (likely(nd->depth != EMBEDDED_LEVELS))
@@ -1296,6 +1314,8 @@ static int follow_dotdot_rcu(struct nameidata *nd)
return -ECHILD;
nd->path.dentry = parent;
nd->seq = seq;
+ if (unlikely(!path_connected(&nd->path)))
+ return -ENOENT;
break;
} else {
struct mount *mnt = real_mount(nd->path.mnt);
@@ -1396,7 +1416,7 @@ static void follow_mount(struct path *path)
}
}
-static void follow_dotdot(struct nameidata *nd)
+static int follow_dotdot(struct nameidata *nd)
{
if (!nd->root.mnt)
set_root(nd);
@@ -1412,6 +1432,8 @@ static void follow_dotdot(struct nameidata *nd)
/* rare case of legitimate dget_parent()... */
nd->path.dentry = dget_parent(nd->path.dentry);
dput(old);
+ if (unlikely(!path_connected(&nd->path)))
+ return -ENOENT;
break;
}
if (!follow_up(&nd->path))
@@ -1419,6 +1441,7 @@ static void follow_dotdot(struct nameidata *nd)
}
follow_mount(&nd->path);
nd->inode = nd->path.dentry->d_inode;
+ return 0;
}
/*
@@ -1634,7 +1657,7 @@ static inline int handle_dots(struct nameidata *nd, int type)
if (nd->flags & LOOKUP_RCU) {
return follow_dotdot_rcu(nd);
} else
- follow_dotdot(nd);
+ return follow_dotdot(nd);
}
return 0;
}
--
2.4.3