Refactor ima_dump_measurement_list() to move the memory allocation part
to a separate function ima_alloc_kexec_file_buf() which allocates buffer
of size 'kexec_segment_size' at kexec 'load'. Make the local variable
ima_kexec_file in function ima_dump_measurement_list() as local static to
the file, so that it can be accessed from ima_alloc_kexec_file_buf().
Make necessary changes to the function ima_add_kexec_buffer() to call the
above two functions.
Signed-off-by: Tushar Sugandhi <tusharsu@xxxxxxxxxxxxxxxxxxx>
---
security/integrity/ima/ima_kexec.c | 96 +++++++++++++++++++++---------
1 file changed, 67 insertions(+), 29 deletions(-)
diff --git a/security/integrity/ima/ima_kexec.c b/security/integrity/ima/ima_kexec.c
index 419dc405c831..99daac355c70 100644
--- a/security/integrity/ima/ima_kexec.c
+++ b/security/integrity/ima/ima_kexec.c
@@ -15,62 +15,93 @@
#include "ima.h"
#ifdef CONFIG_IMA_KEXEC
+static struct seq_file ima_kexec_file;
+
+static void ima_free_kexec_file_buf(struct seq_file *sf)
+{
+ vfree(sf->buf);
+ sf->buf = NULL;
+ sf->size = 0;
+ sf->read_pos = 0;
+ sf->count = 0;
+}
+
+static int ima_alloc_kexec_file_buf(size_t segment_size)
+{
+ /*
+ * kexec 'load' may be called multiple times.
+ * Free and realloc the buffer only if the segment_size is
+ * changed from the previous kexec 'load' call.
+ */
+ if (ima_kexec_file.buf &&
+ ima_kexec_file.size == segment_size &&
+ ima_kexec_file.read_pos == 0 &&
+ ima_kexec_file.count == sizeof(struct ima_kexec_hdr))
+ return 0;
+
+ ima_free_kexec_file_buf(&ima_kexec_file);
+
+ /* segment size can't change between kexec load and execute */
+ ima_kexec_file.buf = vmalloc(segment_size);
+ if (!ima_kexec_file.buf)
+ return -ENOMEM;
+
+ ima_kexec_file.size = segment_size;
+ ima_kexec_file.read_pos = 0;
+ ima_kexec_file.count = sizeof(struct ima_kexec_hdr); /* reserved space */
+
+ return 0;
+}
+
static int ima_dump_measurement_list(unsigned long *buffer_size, void **buffer,
unsigned long segment_size)
{
struct ima_queue_entry *qe;
- struct seq_file file;
struct ima_kexec_hdr khdr;
- int ret = 0;
- /* segment size can't change between kexec load and execute */
- file.buf = vmalloc(segment_size);
- if (!file.buf) {
- ret = -ENOMEM;
- goto out;
+ if (!ima_kexec_file.buf) {
+ *buffer_size = 0;
+ *buffer = NULL;
+ pr_err("%s: Kexec file buf not allocated\n", __func__);
+ return -EINVAL;
}
- file.size = segment_size;
- file.read_pos = 0;
- file.count = sizeof(khdr); /* reserved space */
-
memset(&khdr, 0, sizeof(khdr));
khdr.version = 1;
+
+ /* Copy as many IMA measurements list records as possible */
list_for_each_entry_rcu(qe, &ima_measurements, later) {
- if (file.count < file.size) {
+ if (ima_kexec_file.count < ima_kexec_file.size) {
khdr.count++;
- ima_measurements_show(&file, qe);
+ ima_measurements_show(&ima_kexec_file, qe);
} else {
- ret = -EINVAL;
+ pr_err("%s: IMA log file is too big for Kexec buf\n",
+ __func__);
break;
}
}
- if (ret < 0)
- goto out;
-
/*
* fill in reserved space with some buffer details
* (eg. version, buffer size, number of measurements)
*/
- khdr.buffer_size = file.count;
+ khdr.buffer_size = ima_kexec_file.count;
if (ima_canonical_fmt) {
khdr.version = cpu_to_le16(khdr.version);
khdr.count = cpu_to_le64(khdr.count);
khdr.buffer_size = cpu_to_le64(khdr.buffer_size);
}
- memcpy(file.buf, &khdr, sizeof(khdr));
+ memcpy(ima_kexec_file.buf, &khdr, sizeof(khdr));
print_hex_dump_debug("ima dump: ", DUMP_PREFIX_NONE, 16, 1,
- file.buf, file.count < 100 ? file.count : 100,
+ ima_kexec_file.buf, ima_kexec_file.count < 100 ?
+ ima_kexec_file.count : 100,
true);
- *buffer_size = file.count;
- *buffer = file.buf;
-out:
- if (ret == -EINVAL)
- vfree(file.buf);
- return ret;
+ *buffer_size = ima_kexec_file.count;
+ *buffer = ima_kexec_file.buf;
+
+ return 0;
}
/*
@@ -108,13 +139,20 @@ void ima_add_kexec_buffer(struct kimage *image)
return;
}
- ima_dump_measurement_list(&kexec_buffer_size, &kexec_buffer,
- kexec_segment_size);
- if (!kexec_buffer) {
+ ret = ima_alloc_kexec_file_buf(kexec_segment_size);
+ if (ret < 0) {
pr_err("Not enough memory for the kexec measurement buffer.\n");
return;
}
+ ret = ima_dump_measurement_list(&kexec_buffer_size, &kexec_buffer,
+ kexec_segment_size);
+ if (ret < 0) {
+ pr_err("%s: Failed to dump IMA measurements. Error:%d.\n",
+ __func__, ret);
+ return;
+ }
+
kbuf.buffer = kexec_buffer;
kbuf.bufsz = kexec_buffer_size;
kbuf.memsz = kexec_segment_size;
--
2.25.1
