ima: Free IMA measurement buffer after kexec syscall

BugLink: https://bugs.launchpad.net/bugs/1918974
[ Upstream commit f31e3386a4e92ba6eda7328cb508462956c94c64 ]

IMA allocates kernel virtual memory to carry forward the measurement
list, from the current kernel to the next kernel on kexec system call,
in ima_add_kexec_buffer() function.  This buffer is not freed before
completing the kexec system call resulting in memory leak.

Add ima_buffer field in "struct kimage" to store the virtual address
of the buffer allocated for the IMA measurement list.
Free the memory allocated for the IMA measurement list in
kimage_file_post_load_cleanup() function.

Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
Suggested-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Reviewed-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Reviewed-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Fixes: 7b8589cc29e7 ("ima: on soft reboot, save the measurement list")
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Kelsey Skunberg <kelsey.skunberg@canonical.com>

diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index 1776eb2e43a444c3b83ffa08806b6361d4444f17..a1cffce3de8cd70a56c463beda9aa31c02f86bab 100644 (file)
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -293,6 +293,11 @@ struct kimage {
        /* Information for loading purgatory */
        struct purgatory_info purgatory_info;
 #endif
+
+#ifdef CONFIG_IMA_KEXEC
+       /* Virtual address of IMA measurement buffer for kexec syscall */
+       void *ima_buffer;
+#endif
 };
 
 /* kexec interface functions */

diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index 79f252af7dee3b98391fcb1058f3e4463973e941..4e74db89bd23ff52078ec24e4de54bbdc5af7779 100644 (file)
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -165,6 +165,11 @@ void kimage_file_post_load_cleanup(struct kimage *image)
        vfree(pi->sechdrs);
        pi->sechdrs = NULL;
 
+#ifdef CONFIG_IMA_KEXEC
+       vfree(image->ima_buffer);
+       image->ima_buffer = NULL;
+#endif /* CONFIG_IMA_KEXEC */
+
        /* See if architecture has anything to cleanup post load */
        arch_kimage_file_post_load_cleanup(image);
 

diff --git a/security/integrity/ima/ima_kexec.c b/security/integrity/ima/ima_kexec.c
index 37b1244e3a166954e9966dbeac665080e791879a..955e4b4d09e21bb01bc77033c1ee6f48aad7fac1 100644 (file)
--- a/security/integrity/ima/ima_kexec.c
+++ b/security/integrity/ima/ima_kexec.c
@@ -130,6 +130,8 @@ void ima_add_kexec_buffer(struct kimage *image)
                return;
        }
 
+       image->ima_buffer = kexec_buffer;
+
        pr_debug("kexec measurement buffer for the loaded kernel at 0x%lx.\n",
                 kbuf.mem);
 }