ima: Free IMA measurement buffer after kexec syscall

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>

1 files changed, 5 insertions, 0 deletions

diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index b02086d70492..5c3447cf7ad5 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -166,6 +166,11 @@ 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);