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From: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
To: robh@kernel.org, dan.carpenter@oracle.com, mpe@ellerman.id.au
Cc: devicetree@vger.kernel.org, kbuild-all@lists.01.org,
	lkp@intel.com, nramas@linux.microsoft.com,
	linuxppc-dev@lists.ozlabs.org, bauerman@linux.ibm.com,
	dja@axtens.net
Subject: [PATCH 1/2] powerpc: Free fdt on error in elf64_load()
Date: Tue, 20 Apr 2021 12:03:54 -0700
Message-ID: <20210420190355.10059-1-nramas@linux.microsoft.com> (raw)

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.

Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Suggested-by: Michael Ellerman <mpe@ellerman.id.au>
---
 arch/powerpc/kexec/elf_64.c | 16 ++++++----------
 1 file changed, 6 insertions(+), 10 deletions(-)

diff --git a/arch/powerpc/kexec/elf_64.c b/arch/powerpc/kexec/elf_64.c
index 5a569bb51349..02662e72c53d 100644
--- 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;
 }
 
-- 
2.31.0


             reply index

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-20 19:03 Lakshmi Ramasubramanian [this message]
2021-04-20 19:03 ` [PATCH 2/2] powerpc: If kexec_build_elf_info() fails return immediately from elf64_load() Lakshmi Ramasubramanian
2021-04-21  7:21   ` Michael Ellerman
2021-04-21  5:35 ` [PATCH 1/2] powerpc: Free fdt on error in elf64_load() Santosh Sivaraj
2021-04-21 13:58   ` Lakshmi Ramasubramanian
2021-04-21 14:02     ` Santosh Sivaraj
2021-04-21  7:18 ` Michael Ellerman
2021-04-21 14:01   ` Lakshmi Ramasubramanian

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