bootstd: Avoid freeing a non-allocated buffer

EFI applications can be very large and thus used to cause boot failures
when malloc() space was exhausted.

A recent changed fixed this by using the kernel_addr_r environment var
as the address of the buffer. However, it still frees the buffer when
the bootflow is discarded.

Fix this by introducing a flag to indicate whether the buffer was
allocated, or not.

Note that kernel_addr_r is not the last word here. It might be better
to use lmb to place images. But there is a lot of refactoring to do
before we can remove the environment variables. The distro scripts rely
on them so it is safe for bootstd to do so too.

Fixes: 6a8c2f9781c bootstd: Avoid allocating memory for the EFI file

Signed-off-by: Simon Glass <sjg@chromium.org>
Reported by: Simon Glass <sjg@chromium.org>
Reported by: Shantur Rathore <i@shantur.com>
Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Tested-by: Shantur Rathore <i@shantur.com>

diff --git a/boot/bootflow.c b/boot/bootflow.c
index 6922e7e..1ea2966 100644 (file)
--- a/boot/bootflow.c
+++ b/boot/bootflow.c
@@ -467,7 +467,8 @@ void bootflow_free(struct bootflow *bflow)
        free(bflow->name);
        free(bflow->subdir);
        free(bflow->fname);
-       free(bflow->buf);
+       if (!(bflow->flags & BOOTFLOWF_STATIC_BUF))
+               free(bflow->buf);
        free(bflow->os_name);
        free(bflow->fdt_fname);
        free(bflow->bootmeth_priv);

diff --git a/boot/bootmeth_efi.c b/boot/bootmeth_efi.c
index ae936c8..9ba7734 100644 (file)
--- a/boot/bootmeth_efi.c
+++ b/boot/bootmeth_efi.c
@@ -160,6 +160,7 @@ static int efiload_read_file(struct bootflow *bflow, ulong addr)
        if (ret)
                return log_msg_ret("read", ret);
        bflow->buf = map_sysmem(addr, bflow->size);
+       bflow->flags |= BOOTFLOWF_STATIC_BUF;
 
        set_efi_bootdev(desc, bflow);
 

diff --git a/include/bootflow.h b/include/bootflow.h
index 44d3741..fede8f2 100644 (file)
--- a/include/bootflow.h
+++ b/include/bootflow.h
@@ -43,9 +43,12 @@ enum bootflow_state_t {
  *     and it is using the prior-stage FDT, which is the U-Boot control FDT.
  *     This is only possible with the EFI bootmeth (distro-efi) and only when
  *     CONFIG_OF_HAS_PRIOR_STAGE is enabled
+ * @BOOTFLOWF_STATIC_BUF: Indicates that @bflow->buf is statically set, rather
+ *     than being allocated by malloc().
  */
 enum bootflow_flags_t {
        BOOTFLOWF_USE_PRIOR_FDT = 1 << 0,
+       BOOTFLOWF_STATIC_BUF    = 1 << 1,
 };
 
 /**
@@ -72,7 +75,7 @@ enum bootflow_flags_t {
  * @fname: Filename of bootflow file (allocated)
  * @logo: Logo to display for this bootflow (BMP format)
  * @logo_size: Size of the logo in bytes
- * @buf: Bootflow file contents (allocated)
+ * @buf: Bootflow file contents (allocated unless @flags & BOOTFLOWF_STATIC_BUF)
  * @size: Size of bootflow file in bytes
  * @err: Error number received (0 if OK)
  * @os_name: Name of the OS / distro being booted, or NULL if not known