ima: Free IMA measurement buffer after kexec syscall

[ 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>

diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index 1c08c925cefbb748e0255486e30be309d70c497f..1ce6ba5f04077d0cce879a7885cac0502b8e3190 100644 (file)
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -217,6 +217,11 @@ 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 9f48f441229720b0e02434b2375b61d9c62b7706..6d0bdedb2e20719a913725222cc8d4d0d6799d65 100644 (file)
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -95,6 +95,11 @@ 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 40bc385a8076809044410d3371e7c631f44cac7f..ce30e6edfedc4a1c14575e887a6b72aa9aa96a1f 100644 (file)
--- a/security/integrity/ima/ima_kexec.c
+++ b/security/integrity/ima/ima_kexec.c
@@ -132,6 +132,8 @@ 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);
 }