efi/capsule-loader: Use a cached copy of the capsule header

Instead of kmapping the capsule data twice, copy the capsule header
into the capsule info struct we keep locally. This is an improvement
by itself, but will also enable handling of non-standard header formats
more easily.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/20170602135207.21708-7-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/drivers/firmware/efi/capsule-loader.c b/drivers/firmware/efi/capsule-loader.c
index 37d3f6ec2d285aa898ff2075b9e1ded9e1838ce7..5b012a467d7d62b0f8f0c87b7fd1b3c020a87f5e 100644 (file)
--- a/drivers/firmware/efi/capsule-loader.c
+++ b/drivers/firmware/efi/capsule-loader.c
@@ -21,13 +21,13 @@
 #define NO_FURTHER_WRITE_ACTION -1
 
 struct capsule_info {
-       bool            header_obtained;
-       int             reset_type;
-       long            index;
-       size_t          count;
-       size_t          total_size;
-       struct page     **pages;
-       size_t          page_bytes_remain;
+       efi_capsule_header_t    header;
+       int                     reset_type;
+       long                    index;
+       size_t                  count;
+       size_t                  total_size;
+       struct page             **pages;
+       size_t                  page_bytes_remain;
 };
 
 /**
@@ -56,7 +56,6 @@ static void efi_free_all_buff_pages(struct capsule_info *cap_info)
 static int efi_capsule_setup_info(struct capsule_info *cap_info,
                                  void *kbuff, size_t hdr_bytes)
 {
-       efi_capsule_header_t *cap_hdr;
        size_t pages_needed;
        int ret;
        void *temp_page;
@@ -66,8 +65,9 @@ static int efi_capsule_setup_info(struct capsule_info *cap_info,
                return 0;
 
        /* Reset back to the correct offset of header */
-       cap_hdr = kbuff - cap_info->count;
-       pages_needed = ALIGN(cap_hdr->imagesize, PAGE_SIZE) >> PAGE_SHIFT;
+       kbuff -= cap_info->count;
+       memcpy(&cap_info->header, kbuff, sizeof(cap_info->header));
+       pages_needed = ALIGN(cap_info->header.imagesize, PAGE_SIZE) / PAGE_SIZE;
 
        if (pages_needed == 0) {
                pr_err("invalid capsule size");
@@ -75,15 +75,16 @@ static int efi_capsule_setup_info(struct capsule_info *cap_info,
        }
 
        /* Check if the capsule binary supported */
-       ret = efi_capsule_supported(cap_hdr->guid, cap_hdr->flags,
-                                   cap_hdr->imagesize,
+       ret = efi_capsule_supported(cap_info->header.guid,
+                                   cap_info->header.flags,
+                                   cap_info->header.imagesize,
                                    &cap_info->reset_type);
        if (ret) {
                pr_err("capsule not supported\n");
                return ret;
        }
 
-       cap_info->total_size = cap_hdr->imagesize;
+       cap_info->total_size = cap_info->header.imagesize;
        temp_page = krealloc(cap_info->pages,
                             pages_needed * sizeof(void *),
                             GFP_KERNEL | __GFP_ZERO);
@@ -91,7 +92,6 @@ static int efi_capsule_setup_info(struct capsule_info *cap_info,
                return -ENOMEM;
 
        cap_info->pages = temp_page;
-       cap_info->header_obtained = true;
 
        return 0;
 }
@@ -104,15 +104,8 @@ static int efi_capsule_setup_info(struct capsule_info *cap_info,
 static ssize_t efi_capsule_submit_update(struct capsule_info *cap_info)
 {
        int ret;
-       void *cap_hdr_temp;
 
-       cap_hdr_temp = vmap(cap_info->pages, cap_info->index,
-                       VM_MAP, PAGE_KERNEL);
-       if (!cap_hdr_temp)
-               return -ENOMEM;
-
-       ret = efi_capsule_update(cap_hdr_temp, cap_info->pages);
-       vunmap(cap_hdr_temp);
+       ret = efi_capsule_update(&cap_info->header, cap_info->pages);
        if (ret) {
                pr_err("capsule update failed\n");
                return ret;
@@ -192,7 +185,7 @@ static ssize_t efi_capsule_write(struct file *file, const char __user *buff,
        cap_info->page_bytes_remain -= write_byte;
 
        /* Setup capsule binary info structure */
-       if (!cap_info->header_obtained) {
+       if (cap_info->header.headersize == 0) {
                ret = efi_capsule_setup_info(cap_info, kbuff,
                                             cap_info->count + write_byte);
                if (ret)
@@ -203,7 +196,7 @@ static ssize_t efi_capsule_write(struct file *file, const char __user *buff,
        kunmap(page);
 
        /* Submit the full binary to efi_capsule_update() API */
-       if (cap_info->header_obtained &&
+       if (cap_info->header.headersize > 0 &&
            cap_info->count >= cap_info->total_size) {
                if (cap_info->count > cap_info->total_size) {
                        pr_err("capsule upload size exceeded header defined size\n");