diff options
| author | Mimi Zohar <zohar@linux.ibm.com> | 2025-01-27 10:45:48 -0500 |
|---|---|---|
| committer | Mimi Zohar <zohar@linux.ibm.com> | 2025-03-27 12:40:12 -0400 |
| commit | a414016218ca97140171aa3bb926b02e1f68c2cc (patch) | |
| tree | a04429b21fb96d9eed41200ccb31eb16b03ad847 /security | |
| parent | 5b3cd801155f0b34b0b95942a5b057c9b8cad33e (diff) | |
ima: limit the number of ToMToU integrity violations
Each time a file in policy, that is already opened for read, is opened
for write, a Time-of-Measure-Time-of-Use (ToMToU) integrity violation
audit message is emitted and a violation record is added to the IMA
measurement list. This occurs even if a ToMToU violation has already
been recorded.
Limit the number of ToMToU integrity violations per file open for read.
Note: The IMA_MAY_EMIT_TOMTOU atomic flag must be set from the reader
side based on policy. This may result in a per file open for read
ToMToU violation.
Since IMA_MUST_MEASURE is only used for violations, rename the atomic
IMA_MUST_MEASURE flag to IMA_MAY_EMIT_TOMTOU.
Cc: stable@vger.kernel.org # applies cleanly up to linux-6.6
Tested-by: Stefan Berger <stefanb@linux.ibm.com>
Reviewed-by: Petr Vorel <pvorel@suse.cz>
Tested-by: Petr Vorel <pvorel@suse.cz>
Reviewed-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
Diffstat (limited to 'security')
| -rw-r--r-- | security/integrity/ima/ima.h | 2 | ||||
| -rw-r--r-- | security/integrity/ima/ima_main.c | 7 |
2 files changed, 5 insertions, 4 deletions
diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h index 3423b3088de5..e0489c6f7f59 100644 --- a/security/integrity/ima/ima.h +++ b/security/integrity/ima/ima.h @@ -181,7 +181,7 @@ struct ima_kexec_hdr { #define IMA_UPDATE_XATTR 1 #define IMA_CHANGE_ATTR 2 #define IMA_DIGSIG 3 -#define IMA_MUST_MEASURE 4 +#define IMA_MAY_EMIT_TOMTOU 4 #define IMA_EMITTED_OPENWRITERS 5 /* IMA integrity metadata associated with an inode */ diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c index 95118c1887cb..f3e7ac513db3 100644 --- a/security/integrity/ima/ima_main.c +++ b/security/integrity/ima/ima_main.c @@ -129,14 +129,15 @@ static void ima_rdwr_violation_check(struct file *file, if (atomic_read(&inode->i_readcount) && IS_IMA(inode)) { if (!iint) iint = ima_iint_find(inode); + /* IMA_MEASURE is set from reader side */ - if (iint && test_bit(IMA_MUST_MEASURE, - &iint->atomic_flags)) + if (iint && test_and_clear_bit(IMA_MAY_EMIT_TOMTOU, + &iint->atomic_flags)) send_tomtou = true; } } else { if (must_measure) - set_bit(IMA_MUST_MEASURE, &iint->atomic_flags); + set_bit(IMA_MAY_EMIT_TOMTOU, &iint->atomic_flags); /* Limit number of open_writers violations */ if (inode_is_open_for_write(inode) && must_measure) { |