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firmware: replace call to fw_read_file_contents() with kernel version

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Replace the fw_read_file_contents with kernel_file_read_from_path().

Although none of the upstreamed LSMs define a kernel_fw_from_file hook,
IMA is called by the security function to prevent unsigned firmware from
being loaded and to measure/appraise signed firmware, based on policy.

Instead of reading the firmware twice, once for measuring/appraising the
firmware and again for reading the firmware contents into memory, the
kernel_post_read_file() security hook calculates the file hash based on
the in memory file buffer.  The firmware is read once.

This patch removes the LSM kernel_fw_from_file() hook and security call.

Changelog v4+:
- revert dropped buf->size assignment - reported by Sergey Senozhatsky
v3:
- remove kernel_fw_from_file hook
- use kernel_file_read_from_path() - requested by Luis
v2:
- reordered and squashed firmware patches
- fix MAX firmware size (Kees Cook)

Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Luis R. Rodriguez <mcgrof@kernel.org>
This commit is contained in:
Mimi Zohar
2015-11-19 12:39:22 -05:00
parent 09596b94f7
commit e40ba6d56b
7 changed files with 21 additions and 90 deletions
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21
security/integrity/ima/ima_main.c
View File

@@ -337,17 +337,6 @@ int ima_module_check(struct file *file)
return process_measurement(file, NULL, 0, MAY_EXEC, MODULE_CHECK, 0);
}
int ima_fw_from_file(struct file *file, char *buf, size_t size)
{
if (!file) {
if ((ima_appraise & IMA_APPRAISE_FIRMWARE) &&
(ima_appraise & IMA_APPRAISE_ENFORCE))
return -EACCES; /* INTEGRITY_UNKNOWN */
return 0;
}
return process_measurement(file, NULL, 0, MAY_EXEC, FIRMWARE_CHECK, 0);
}
/**
* ima_post_read_file - in memory collect/appraise/audit measurement
* @file: pointer to the file to be measured/appraised/audit
@@ -366,12 +355,22 @@ int ima_post_read_file(struct file *file, void *buf, loff_t size,
{
enum ima_hooks func = FILE_CHECK;
if (!file && read_id == READING_FIRMWARE) {
if ((ima_appraise & IMA_APPRAISE_FIRMWARE) &&
(ima_appraise & IMA_APPRAISE_ENFORCE))
return -EACCES; /* INTEGRITY_UNKNOWN */
return 0;
}
if (!file || !buf || size == 0) { /* should never happen */
if (ima_appraise & IMA_APPRAISE_ENFORCE)
return -EACCES;
return 0;
}
if (read_id == READING_FIRMWARE)
func = FIRMWARE_CHECK;
return process_measurement(file, buf, size, MAY_READ, func, 0);
}