6.13-stable review patch. If anyone has any objections, please let me know.
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From: Mimi Zohar zohar@linux.ibm.com
commit a414016218ca97140171aa3bb926b02e1f68c2cc upstream.
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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- security/integrity/ima/ima.h | 2 +- security/integrity/ima/ima_main.c | 7 ++++--- 2 files changed, 5 insertions(+), 4 deletions(-)
--- 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 */ --- a/security/integrity/ima/ima_main.c +++ b/security/integrity/ima/ima_main.c @@ -129,14 +129,15 @@ static void ima_rdwr_violation_check(str 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) {