| Message ID | 20210629123533.1191246-1-christian.brauner@ubuntu.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [GIT,PULL] openat2 fixes | expand |
The pull request you sent on Tue, 29 Jun 2021 14:35:33 +0200:
> git@gitolite.kernel.org:pub/scm/linux/kernel/git/brauner/linux tags/fs.openat2.unknown_flags.v5.14
has been merged into torvalds/linux.git:
https://git.kernel.org/torvalds/c/b97902b62ae8d5bdd20f56278d8083b4324bf7b5
Thank you!
Hi Linus, /* Summary */ - Remove the unused VALID_UPGRADE_FLAGS define we carried from an extension to openat2() that we haven't merged. Aleksa might be getting back to it at some point but just not right now. - openat2() used to accidently ignore unknown flag values in the upper 32 bits. The new openat2() syscall verifies that no unknown O-flag values are set and returns an error to userspace if they are while the older open syscalls like open() and openat() simply ignore unknown flag values: #define O_FLAG_CURRENTLY_INVALID (1 << 31) struct open_how how = { .flags = O_RDONLY | O_FLAG_CURRENTLY_INVALID, .resolve = 0, }; /* fails */ fd = openat2(-EBADF, "/dev/null", &how, sizeof(how)); /* succeeds */ fd = openat(-EBADF, "/dev/null", O_RDONLY | O_FLAG_CURRENTLY_INVALID); However, openat2() silently truncates the upper 32 bits meaning: #define O_FLAG_CURRENTLY_INVALID_LOWER32 (1 << 31) #define O_FLAG_CURRENTLY_INVALID_UPPER32 (1 << 40) struct open_how how_lowe32 = { .flags = O_RDONLY | O_FLAG_CURRENTLY_INVALID_LOWER32, }; struct open_how how_upper32 = { .flags = O_RDONLY | O_FLAG_CURRENTLY_INVALID_UPPER32, }; /* fails */ fd = openat2(-EBADF, "/dev/null", &how_lower32, sizeof(how_lower32)); /* succeeds */ fd = openat2(-EBADF, "/dev/null", &how_upper32, sizeof(how_upper32)); Fix this by preventing the immediate truncation in build_open_flags() and add a compile-time check to catch when we add flags in the upper 32 bit range. /* Testing */ All patches are based on v5.13-rc3 and have been sitting in linux-next. No build failures or warnings were observed. All old and new tests are passing. /* Conflicts */ At the time of creating this PR no merge conflicts were reported from linux-next and no merge conflicts showed up doing a test-merge with current mainline. The following changes since commit c4681547bcce777daf576925a966ffa824edd09d: Linux 5.13-rc3 (2021-05-23 11:42:48 -1000) are available in the Git repository at: git@gitolite.kernel.org:pub/scm/linux/kernel/git/brauner/linux tags/fs.openat2.unknown_flags.v5.14 for you to fetch changes up to 15845cbcd12a571869c6703892427f9e5839d5fb: test: add openat2() test for invalid upper 32 bit flag value (2021-05-28 17:44:37 +0200) Please consider pulling these changes from the signed fs.openat2.unknown_flags.v5.14 tag. Thanks! Christian ---------------------------------------------------------------- fs.openat2.unknown_flags.v5.14 ---------------------------------------------------------------- Christian Brauner (3): fcntl: remove unused VALID_UPGRADE_FLAGS open: don't silently ignore unknown O-flags in openat2() test: add openat2() test for invalid upper 32 bit flag value fs/open.c | 14 +++++++++++--- include/linux/fcntl.h | 4 ---- tools/testing/selftests/openat2/openat2_test.c | 7 ++++++- 3 files changed, 17 insertions(+), 8 deletions(-)