powerpc: Free fdt on error in elf64_load()

There are a few "goto out;" statements before the local variable "fdt"
is initialized through the call to of_kexec_alloc_and_setup_fdt() in
elf64_load().  This will result in an uninitialized "fdt" being passed
to kvfree() in this function if there is an error before the call to
of_kexec_alloc_and_setup_fdt().

If there is any error after fdt is allocated, but before it is
saved in the arch specific kimage struct, free the fdt.

Fixes: 3c985d31ad66 ("powerpc: Use common of_kexec_alloc_and_setup_fdt()")
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20210421163610.23775-1-nramas@linux.microsoft.com

diff --git a/arch/powerpc/kexec/elf_64.c b/arch/powerpc/kexec/elf_64.c
index 5a569bb513498478d545a3d08ff41bd2fdebbf9a..02662e72c53dc4557b4b32a5f555975665e22adc 100644 (file)
--- a/arch/powerpc/kexec/elf_64.c
+++ b/arch/powerpc/kexec/elf_64.c
@@ -114,7 +114,7 @@ static void *elf64_load(struct kimage *image, char *kernel_buf,
        ret = setup_new_fdt_ppc64(image, fdt, initrd_load_addr,
                                  initrd_len, cmdline);
        if (ret)
-               goto out;
+               goto out_free_fdt;
 
        fdt_pack(fdt);
 
@@ -125,7 +125,7 @@ static void *elf64_load(struct kimage *image, char *kernel_buf,
        kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
        ret = kexec_add_buffer(&kbuf);
        if (ret)
-               goto out;
+               goto out_free_fdt;
 
        /* FDT will be freed in arch_kimage_file_post_load_cleanup */
        image->arch.fdt = fdt;
@@ -140,18 +140,14 @@ static void *elf64_load(struct kimage *image, char *kernel_buf,
        if (ret)
                pr_err("Error setting up the purgatory.\n");
 
+       goto out;
+
+out_free_fdt:
+       kvfree(fdt);
 out:
        kfree(modified_cmdline);
        kexec_free_elf_info(&elf_info);
 
-       /*
-        * Once FDT buffer has been successfully passed to kexec_add_buffer(),
-        * the FDT buffer address is saved in image->arch.fdt. In that case,
-        * the memory cannot be freed here in case of any other error.
-        */
-       if (ret && !image->arch.fdt)
-               kvfree(fdt);
-
        return ret ? ERR_PTR(ret) : NULL;
 }