The commit 315db9a05b7a ("cifs: fix leak in cifs_smb3_do_mount() ctx") revealed an existing bug when mounting shares that contain a prefix path or DFS links.
cifs_setup_volume_info() requires the @devname to contain the full path (UNC + prefix) to update the fs context with the new UNC and prepath values, however we were passing only the UNC path (old_ctx->UNC) in @device thus discarding any prefix paths.
Instead of concatenating both old_ctx->{UNC,prepath} and pass it in @devname, just keep the dup'ed values of UNC and prepath in cifs_sb->ctx after calling smb3_fs_context_dup(), and fix smb3_parse_devname() to correctly parse and not leak the new UNC and prefix paths.
Cc: stable@vger.kernel.org # v5.11+ Fixes: 315db9a05b7a ("cifs: fix leak in cifs_smb3_do_mount() ctx") Signed-off-by: Paulo Alcantara (SUSE) pc@cjr.nz --- fs/cifs/cifsfs.c | 8 +------- fs/cifs/connect.c | 25 +++++++++++++++++-------- fs/cifs/fs_context.c | 4 ++++ 3 files changed, 22 insertions(+), 15 deletions(-)
diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c index 8a6894577697..d7ea9c5fe0f8 100644 --- a/fs/cifs/cifsfs.c +++ b/fs/cifs/cifsfs.c @@ -863,13 +863,7 @@ cifs_smb3_do_mount(struct file_system_type *fs_type, goto out; }
- /* cifs_setup_volume_info->smb3_parse_devname() redups UNC & prepath */ - kfree(cifs_sb->ctx->UNC); - cifs_sb->ctx->UNC = NULL; - kfree(cifs_sb->ctx->prepath); - cifs_sb->ctx->prepath = NULL; - - rc = cifs_setup_volume_info(cifs_sb->ctx, NULL, old_ctx->UNC); + rc = cifs_setup_volume_info(cifs_sb->ctx, NULL, NULL); if (rc) { root = ERR_PTR(rc); goto out; diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c index becd5f807787..04a06e22e715 100644 --- a/fs/cifs/connect.c +++ b/fs/cifs/connect.c @@ -3159,19 +3159,28 @@ static int do_dfs_failover(const char *path, const char *full_path, struct cifs_ int cifs_setup_volume_info(struct smb3_fs_context *ctx, const char *mntopts, const char *devname) { - int rc = 0; + int rc;
- smb3_parse_devname(devname, ctx); + if (devname) { + cifs_dbg(FYI, "%s: devname=%s\n", __func__, devname); + rc = smb3_parse_devname(devname, ctx); + if (rc) { + cifs_dbg(VFS, "%s: failed to parse %s: %d\n", __func__, devname, rc); + return rc; + } + }
if (mntopts) { char *ip;
- cifs_dbg(FYI, "%s: mntopts=%s\n", __func__, mntopts); rc = smb3_parse_opt(mntopts, "ip", &ip); - if (!rc && !cifs_convert_address((struct sockaddr *)&ctx->dstaddr, ip, - strlen(ip))) { - cifs_dbg(VFS, "%s: failed to convert ip address\n", __func__); - return -EINVAL; + if (!rc) { + rc = cifs_convert_address((struct sockaddr *)&ctx->dstaddr, ip, strlen(ip)); + kfree(ip); + if (!rc) { + cifs_dbg(VFS, "%s: failed to convert ip address\n", __func__); + return -EINVAL; + } } }
@@ -3189,7 +3198,7 @@ cifs_setup_volume_info(struct smb3_fs_context *ctx, const char *mntopts, const c return -EINVAL; }
- return rc; + return 0; }
static int diff --git a/fs/cifs/fs_context.c b/fs/cifs/fs_context.c index 1d6e0e15b034..3bcf881c3ae9 100644 --- a/fs/cifs/fs_context.c +++ b/fs/cifs/fs_context.c @@ -476,6 +476,7 @@ smb3_parse_devname(const char *devname, struct smb3_fs_context *ctx)
/* move "pos" up to delimiter or NULL */ pos += len; + kfree(ctx->UNC); ctx->UNC = kstrndup(devname, pos - devname, GFP_KERNEL); if (!ctx->UNC) return -ENOMEM; @@ -486,6 +487,9 @@ smb3_parse_devname(const char *devname, struct smb3_fs_context *ctx) if (*pos == '/' || *pos == '\') pos++;
+ kfree(ctx->prepath); + ctx->prepath = NULL; + /* If pos is NULL then no prepath */ if (!*pos) return 0;
On Fri, 30 Apr 2021 19:16:21 -0300, Paulo Alcantara wrote:
The commit 315db9a05b7a ("cifs: fix leak in cifs_smb3_do_mount() ctx") revealed an existing bug when mounting shares that contain a prefix path or DFS links.
Sorry for the mess. One question...
...
if (mntopts) { char *ip;
cifs_dbg(FYI, "%s: mntopts=%s\n", __func__, mntopts);if (!rc && !cifs_convert_address((struct sockaddr *)&ctx->dstaddr, ip,strlen(ip))) {cifs_dbg(VFS, "%s: failed to convert ip address\n", __func__);return -EINVAL;
if (!rc) {rc = cifs_convert_address((struct sockaddr *)&ctx->dstaddr, ip, strlen(ip));kfree(ip);if (!rc) {cifs_dbg(VFS, "%s: failed to convert ip address\n", __func__);return -EINVAL;}@@ -3189,7 +3198,7 @@ cifs_setup_volume_info(struct smb3_fs_context *ctx, const char *mntopts, const c return -EINVAL; }
- return rc;
- return 0;
}
It seems that smb3_parse_opt() errors will no longer be propagated here. Is that intentional?
Cheers, David
David Disseldorp ddiss@suse.de writes:
On Fri, 30 Apr 2021 19:16:21 -0300, Paulo Alcantara wrote:
The commit 315db9a05b7a ("cifs: fix leak in cifs_smb3_do_mount() ctx") revealed an existing bug when mounting shares that contain a prefix path or DFS links.
Sorry for the mess. One question...
...
if (mntopts) { char *ip;
cifs_dbg(FYI, "%s: mntopts=%s\n", __func__, mntopts);if (!rc && !cifs_convert_address((struct sockaddr *)&ctx->dstaddr, ip,strlen(ip))) {cifs_dbg(VFS, "%s: failed to convert ip address\n", __func__);return -EINVAL;
if (!rc) {rc = cifs_convert_address((struct sockaddr *)&ctx->dstaddr, ip, strlen(ip));kfree(ip);if (!rc) {cifs_dbg(VFS, "%s: failed to convert ip address\n", __func__);return -EINVAL;}@@ -3189,7 +3198,7 @@ cifs_setup_volume_info(struct smb3_fs_context *ctx, const char *mntopts, const c return -EINVAL; }
- return rc;
- return 0;
}
It seems that smb3_parse_opt() errors will no longer be propagated here. Is that intentional?
That was a mistake, actually. Will fix it in v2. Thanks!
The commit 315db9a05b7a ("cifs: fix leak in cifs_smb3_do_mount() ctx") revealed an existing bug when mounting shares that contain a prefix path or DFS links.
cifs_setup_volume_info() requires the @devname to contain the full path (UNC + prefix) to update the fs context with the new UNC and prepath values, however we were passing only the UNC path (old_ctx->UNC) in @device thus discarding any prefix paths.
Instead of concatenating both old_ctx->{UNC,prepath} and pass it in @devname, just keep the dup'ed values of UNC and prepath in cifs_sb->ctx after calling smb3_fs_context_dup(), and fix smb3_parse_devname() to correctly parse and not leak the new UNC and prefix paths.
Cc: stable@vger.kernel.org # v5.11+ Fixes: 315db9a05b7a ("cifs: fix leak in cifs_smb3_do_mount() ctx") Signed-off-by: Paulo Alcantara (SUSE) pc@cjr.nz --- fs/cifs/cifsfs.c | 8 +------- fs/cifs/connect.c | 24 ++++++++++++++++++------ fs/cifs/fs_context.c | 4 ++++ 3 files changed, 23 insertions(+), 13 deletions(-)
diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c index 8a6894577697..d7ea9c5fe0f8 100644 --- a/fs/cifs/cifsfs.c +++ b/fs/cifs/cifsfs.c @@ -863,13 +863,7 @@ cifs_smb3_do_mount(struct file_system_type *fs_type, goto out; }
- /* cifs_setup_volume_info->smb3_parse_devname() redups UNC & prepath */ - kfree(cifs_sb->ctx->UNC); - cifs_sb->ctx->UNC = NULL; - kfree(cifs_sb->ctx->prepath); - cifs_sb->ctx->prepath = NULL; - - rc = cifs_setup_volume_info(cifs_sb->ctx, NULL, old_ctx->UNC); + rc = cifs_setup_volume_info(cifs_sb->ctx, NULL, NULL); if (rc) { root = ERR_PTR(rc); goto out; diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c index becd5f807787..4ce6fc24cae1 100644 --- a/fs/cifs/connect.c +++ b/fs/cifs/connect.c @@ -3159,17 +3159,29 @@ static int do_dfs_failover(const char *path, const char *full_path, struct cifs_ int cifs_setup_volume_info(struct smb3_fs_context *ctx, const char *mntopts, const char *devname) { - int rc = 0; + int rc;
- smb3_parse_devname(devname, ctx); + if (devname) { + cifs_dbg(FYI, "%s: devname=%s\n", __func__, devname); + rc = smb3_parse_devname(devname, ctx); + if (rc) { + cifs_dbg(VFS, "%s: failed to parse %s: %d\n", __func__, devname, rc); + return rc; + } + }
if (mntopts) { char *ip;
- cifs_dbg(FYI, "%s: mntopts=%s\n", __func__, mntopts); rc = smb3_parse_opt(mntopts, "ip", &ip); - if (!rc && !cifs_convert_address((struct sockaddr *)&ctx->dstaddr, ip, - strlen(ip))) { + if (rc) { + cifs_dbg(VFS, "%s: failed to parse ip options: %d\n", __func__, rc); + return rc; + } + + rc = cifs_convert_address((struct sockaddr *)&ctx->dstaddr, ip, strlen(ip)); + kfree(ip); + if (!rc) { cifs_dbg(VFS, "%s: failed to convert ip address\n", __func__); return -EINVAL; } @@ -3189,7 +3201,7 @@ cifs_setup_volume_info(struct smb3_fs_context *ctx, const char *mntopts, const c return -EINVAL; }
- return rc; + return 0; }
static int diff --git a/fs/cifs/fs_context.c b/fs/cifs/fs_context.c index 1d6e0e15b034..3bcf881c3ae9 100644 --- a/fs/cifs/fs_context.c +++ b/fs/cifs/fs_context.c @@ -476,6 +476,7 @@ smb3_parse_devname(const char *devname, struct smb3_fs_context *ctx)
/* move "pos" up to delimiter or NULL */ pos += len; + kfree(ctx->UNC); ctx->UNC = kstrndup(devname, pos - devname, GFP_KERNEL); if (!ctx->UNC) return -ENOMEM; @@ -486,6 +487,9 @@ smb3_parse_devname(const char *devname, struct smb3_fs_context *ctx) if (*pos == '/' || *pos == '\') pos++;
+ kfree(ctx->prepath); + ctx->prepath = NULL; + /* If pos is NULL then no prepath */ if (!*pos) return 0;
On Mon, 3 May 2021 11:55:26 -0300, Paulo Alcantara wrote:
The commit 315db9a05b7a ("cifs: fix leak in cifs_smb3_do_mount() ctx") revealed an existing bug when mounting shares that contain a prefix path or DFS links.
cifs_setup_volume_info() requires the @devname to contain the full path (UNC + prefix) to update the fs context with the new UNC and prepath values, however we were passing only the UNC path (old_ctx->UNC) in @device thus discarding any prefix paths.
Instead of concatenating both old_ctx->{UNC,prepath} and pass it in @devname, just keep the dup'ed values of UNC and prepath in cifs_sb->ctx after calling smb3_fs_context_dup(), and fix smb3_parse_devname() to correctly parse and not leak the new UNC and prefix paths.
Cc: stable@vger.kernel.org # v5.11+ Fixes: 315db9a05b7a ("cifs: fix leak in cifs_smb3_do_mount() ctx") Signed-off-by: Paulo Alcantara (SUSE) pc@cjr.nz
fs/cifs/cifsfs.c | 8 +------- fs/cifs/connect.c | 24 ++++++++++++++++++------ fs/cifs/fs_context.c | 4 ++++ 3 files changed, 23 insertions(+), 13 deletions(-)
diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c index 8a6894577697..d7ea9c5fe0f8 100644 --- a/fs/cifs/cifsfs.c +++ b/fs/cifs/cifsfs.c @@ -863,13 +863,7 @@ cifs_smb3_do_mount(struct file_system_type *fs_type, goto out; }
- /* cifs_setup_volume_info->smb3_parse_devname() redups UNC & prepath */
- kfree(cifs_sb->ctx->UNC);
- cifs_sb->ctx->UNC = NULL;
- kfree(cifs_sb->ctx->prepath);
- cifs_sb->ctx->prepath = NULL;
- rc = cifs_setup_volume_info(cifs_sb->ctx, NULL, old_ctx->UNC);
- rc = cifs_setup_volume_info(cifs_sb->ctx, NULL, NULL);
IIUC, with the new behaviour, this call becomes pretty much an if (!cifs_sb->ctx->username) root = ERR_PTR(-EINVAL);
So it might be worth simplifying this further. Either way: Acked-by: David Disseldorp ddiss@suse.de
Cheers, David
David Disseldorp ddiss@suse.de writes:
On Mon, 3 May 2021 11:55:26 -0300, Paulo Alcantara wrote:
- rc = cifs_setup_volume_info(cifs_sb->ctx, NULL, old_ctx->UNC);
- rc = cifs_setup_volume_info(cifs_sb->ctx, NULL, NULL);
IIUC, with the new behaviour, this call becomes pretty much an if (!cifs_sb->ctx->username) root = ERR_PTR(-EINVAL);
Yeah. We should get rid of the damn thing at some point. I've just tried to keep the logic we currently have in fs/cifs/connect.c by composing new options based upon the chased DFS referrals.
Thanks for pointing it out!
added acked-by and merged into cifs-2.6.git for-next
On Mon, May 3, 2021 at 6:20 PM David Disseldorp ddiss@suse.de wrote:
On Mon, 3 May 2021 11:55:26 -0300, Paulo Alcantara wrote:
The commit 315db9a05b7a ("cifs: fix leak in cifs_smb3_do_mount() ctx") revealed an existing bug when mounting shares that contain a prefix path or DFS links.
cifs_setup_volume_info() requires the @devname to contain the full path (UNC + prefix) to update the fs context with the new UNC and prepath values, however we were passing only the UNC path (old_ctx->UNC) in @device thus discarding any prefix paths.
Instead of concatenating both old_ctx->{UNC,prepath} and pass it in @devname, just keep the dup'ed values of UNC and prepath in cifs_sb->ctx after calling smb3_fs_context_dup(), and fix smb3_parse_devname() to correctly parse and not leak the new UNC and prefix paths.
Cc: stable@vger.kernel.org # v5.11+ Fixes: 315db9a05b7a ("cifs: fix leak in cifs_smb3_do_mount() ctx") Signed-off-by: Paulo Alcantara (SUSE) pc@cjr.nz
fs/cifs/cifsfs.c | 8 +------- fs/cifs/connect.c | 24 ++++++++++++++++++------ fs/cifs/fs_context.c | 4 ++++ 3 files changed, 23 insertions(+), 13 deletions(-)
diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c index 8a6894577697..d7ea9c5fe0f8 100644 --- a/fs/cifs/cifsfs.c +++ b/fs/cifs/cifsfs.c @@ -863,13 +863,7 @@ cifs_smb3_do_mount(struct file_system_type *fs_type, goto out; }
/* cifs_setup_volume_info->smb3_parse_devname() redups UNC & prepath */kfree(cifs_sb->ctx->UNC);cifs_sb->ctx->UNC = NULL;kfree(cifs_sb->ctx->prepath);cifs_sb->ctx->prepath = NULL;rc = cifs_setup_volume_info(cifs_sb->ctx, NULL, old_ctx->UNC);
rc = cifs_setup_volume_info(cifs_sb->ctx, NULL, NULL);IIUC, with the new behaviour, this call becomes pretty much an if (!cifs_sb->ctx->username) root = ERR_PTR(-EINVAL);
So it might be worth simplifying this further. Either way: Acked-by: David Disseldorp ddiss@suse.de
Cheers, David
linux-stable-mirror@lists.linaro.org
-
David Disseldorp -
Paulo Alcantara -
Steve French