Currently there are 2 functions for decompressing compressed image. The
zlib_decompress_file() will determine if the image is compressed by gzip
before read, but lzma_decompress_file() will not. This can cause misleading
information to be printed when the image is not compressed by lzma and
debug option is used:
]# kexec -d -s -l /boot/vmlinuz-5.14.10-300.fc35.x86_64 \
--initrd /boot/initramfs-5.14.10-300.fc35.x86_64.img \
--reuse-cmdline
Try gzip decompression.
Try LZMA decompression.
lzma_decompress_file: read on /boot/vmlinuz-5.14.10-300.fc35.x86_64 of
65536 bytes failed
Add a helper function is_lzma_file() to help behave consistently.
Signed-off-by: Lichen Liu <lichliu@xxxxxxxxxx>
---
kexec/lzma.c | 36 ++++++++++++++++++++++++++++++++++++
1 file changed, 36 insertions(+)
diff --git a/kexec/lzma.c b/kexec/lzma.c
index 5bfccb7..f27cfe2 100644
--- a/kexec/lzma.c
+++ b/kexec/lzma.c
@@ -155,6 +155,39 @@ ssize_t lzread(LZFILE *lzfile, void *buf, size_t len)
}
}
+int is_lzma_file(const char *filename)
+{
+ FILE *fp;
+ int ret = 0;
+ uint8_t buf[13];
+
+ if (!filename)
+ return 0;
+
+ fp = fopen(filename, "r");
+ if (fp == NULL)
+ return 0;
+
+ const size_t size = fread(buf, 1, sizeof(buf), fp);
+
+ if (size != 13)
+ return 0;
+
+ lzma_filter filter = { .id = LZMA_FILTER_LZMA1 };
+
+ switch (lzma_properties_decode(&filter, NULL, buf, 5)) {
+ case LZMA_OK:
+ ret = 1;
+ break;
+ default:
+ /* It's not a lzma file */
+ ret = 0;
+ }
+
+ fclose(fp);
+ return ret;
+}
+
char *lzma_decompress_file(const char *filename, off_t *r_size)
{
LZFILE *fp;
@@ -168,6 +201,9 @@ char *lzma_decompress_file(const char *filename, off_t *r_size)
if (!filename)
return NULL;
+ if (!is_lzma_file(filename))
+ return NULL;
+
fp = lzopen(filename, "rb");
if (fp == 0) {
dbgprintf("Cannot open `%s'\n", filename);
--
2.27.0
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