| Message ID | 20241005140300.19416-6-pali@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | cifs: Improve support for native SMB symlinks | expand |
This looks like one of the more important of the fixes of this series - let me know if any thoughts or Reviewed-by/Acked-by on it. I may try to send this earlier than the others Pali, Let me know if I missed dependencies that this patch depends on On Sat, Oct 5, 2024 at 9:03 AM Pali Rohár <pali@kernel.org> wrote: > > Check that path buffer has correct length (it is non-zero and in UNICODE > mode it has even number of bytes) and check that buffer does not contain > null character (UTF-16 null codepoint in UNICODE mode or null byte in > non-unicode mode) because Linux cannot process symlink with null byte. > > Signed-off-by: Pali Rohár <pali@kernel.org> > --- > fs/smb/client/reparse.c | 19 +++++++++++++++++++ > 1 file changed, 19 insertions(+) > > diff --git a/fs/smb/client/reparse.c b/fs/smb/client/reparse.c > index 0d1cea64ab6e..fb1d16b17f38 100644 > --- a/fs/smb/client/reparse.c > +++ b/fs/smb/client/reparse.c > @@ -544,6 +544,25 @@ int smb2_parse_native_symlink(char **target, const char *buf, unsigned int len, > int rc; > int i; > > + /* Check that length it valid for unicode/non-unicode mode */ > + if (!len || (unicode && (len % 2))) { > + cifs_dbg(VFS, "srv returned malformed symlink buffer\n"); > + rc = -EIO; > + goto out; > + } > + > + /* > + * Check that buffer does not contain UTF-16 null codepoint in unicode > + * mode or null byte in non-unicode mode because Linux cannot process > + * symlink with null byte. > + */ > + if ((unicode && UniStrnlen((wchar_t *)buf, len/2) != len/2) || > + (!unicode && strnlen(buf, len) != len)) { > + cifs_dbg(VFS, "srv returned null byte in native symlink target location\n"); > + rc = -EIO; > + goto out; > + } > + > smb_target = cifs_strndup_from_utf16(buf, len, unicode, cifs_sb->local_nls); > if (!smb_target) { > rc = -ENOMEM; > -- > 2.20.1 > >
On Saturday 12 October 2024 23:21:43 Steve French wrote: > This looks like one of the more important of the fixes of this series > - let me know if any thoughts or Reviewed-by/Acked-by on it. I may > try to send this earlier than the others > > Pali, > Let me know if I missed dependencies that this patch depends on This one should be fine. I do not see any dependency for this change. > On Sat, Oct 5, 2024 at 9:03 AM Pali Rohár <pali@kernel.org> wrote: > > > > Check that path buffer has correct length (it is non-zero and in UNICODE > > mode it has even number of bytes) and check that buffer does not contain > > null character (UTF-16 null codepoint in UNICODE mode or null byte in > > non-unicode mode) because Linux cannot process symlink with null byte. > > > > Signed-off-by: Pali Rohár <pali@kernel.org> > > --- > > fs/smb/client/reparse.c | 19 +++++++++++++++++++ > > 1 file changed, 19 insertions(+) > > > > diff --git a/fs/smb/client/reparse.c b/fs/smb/client/reparse.c > > index 0d1cea64ab6e..fb1d16b17f38 100644 > > --- a/fs/smb/client/reparse.c > > +++ b/fs/smb/client/reparse.c > > @@ -544,6 +544,25 @@ int smb2_parse_native_symlink(char **target, const char *buf, unsigned int len, > > int rc; > > int i; > > > > + /* Check that length it valid for unicode/non-unicode mode */ > > + if (!len || (unicode && (len % 2))) { > > + cifs_dbg(VFS, "srv returned malformed symlink buffer\n"); > > + rc = -EIO; > > + goto out; > > + } > > + > > + /* > > + * Check that buffer does not contain UTF-16 null codepoint in unicode > > + * mode or null byte in non-unicode mode because Linux cannot process > > + * symlink with null byte. > > + */ > > + if ((unicode && UniStrnlen((wchar_t *)buf, len/2) != len/2) || > > + (!unicode && strnlen(buf, len) != len)) { > > + cifs_dbg(VFS, "srv returned null byte in native symlink target location\n"); > > + rc = -EIO; > > + goto out; > > + } > > + > > smb_target = cifs_strndup_from_utf16(buf, len, unicode, cifs_sb->local_nls); > > if (!smb_target) { > > rc = -ENOMEM; > > -- > > 2.20.1 > > > > > > > -- > Thanks, > > Steve
diff --git a/fs/smb/client/reparse.c b/fs/smb/client/reparse.c index 0d1cea64ab6e..fb1d16b17f38 100644 --- a/fs/smb/client/reparse.c +++ b/fs/smb/client/reparse.c @@ -544,6 +544,25 @@ int smb2_parse_native_symlink(char **target, const char *buf, unsigned int len, int rc; int i; + /* Check that length it valid for unicode/non-unicode mode */ + if (!len || (unicode && (len % 2))) { + cifs_dbg(VFS, "srv returned malformed symlink buffer\n"); + rc = -EIO; + goto out; + } + + /* + * Check that buffer does not contain UTF-16 null codepoint in unicode + * mode or null byte in non-unicode mode because Linux cannot process + * symlink with null byte. + */ + if ((unicode && UniStrnlen((wchar_t *)buf, len/2) != len/2) || + (!unicode && strnlen(buf, len) != len)) { + cifs_dbg(VFS, "srv returned null byte in native symlink target location\n"); + rc = -EIO; + goto out; + } + smb_target = cifs_strndup_from_utf16(buf, len, unicode, cifs_sb->local_nls); if (!smb_target) { rc = -ENOMEM;
Check that path buffer has correct length (it is non-zero and in UNICODE mode it has even number of bytes) and check that buffer does not contain null character (UTF-16 null codepoint in UNICODE mode or null byte in non-unicode mode) because Linux cannot process symlink with null byte. Signed-off-by: Pali Rohár <pali@kernel.org> --- fs/smb/client/reparse.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+)