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authorLi Huafei <lihuafei1@huawei.com>2022-11-04 17:56:58 +0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2023-01-07 11:11:53 +0100
commitcdea2da6787583ecca43594132533a2ac8d7cd21 (patch)
treefd6ad230c139139c83106aabbd8bf7f82f782a62 /arch
parentabbb887da77408892c0c8fb4cbbc2a5bb03b140e (diff)
downloadlinux-cdea2da6787583ecca43594132533a2ac8d7cd21.tar.gz
RISC-V: kexec: Fix memory leak of elf header buffer
commit cbc32023ddbdf4baa3d9dc513a2184a84080a5a2 upstream.

This is reported by kmemleak detector:

unreferenced object 0xff2000000403d000 (size 4096):
  comm "kexec", pid 146, jiffies 4294900633 (age 64.792s)
  hex dump (first 32 bytes):
    7f 45 4c 46 02 01 01 00 00 00 00 00 00 00 00 00  .ELF............
    04 00 f3 00 01 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<00000000566ca97c>] kmemleak_vmalloc+0x3c/0xbe
    [<00000000979283d8>] __vmalloc_node_range+0x3ac/0x560
    [<00000000b4b3712a>] __vmalloc_node+0x56/0x62
    [<00000000854f75e2>] vzalloc+0x2c/0x34
    [<00000000e9a00db9>] crash_prepare_elf64_headers+0x80/0x30c
    [<0000000067e8bf48>] elf_kexec_load+0x3e8/0x4ec
    [<0000000036548e09>] kexec_image_load_default+0x40/0x4c
    [<0000000079fbe1b4>] sys_kexec_file_load+0x1c4/0x322
    [<0000000040c62c03>] ret_from_syscall+0x0/0x2

In elf_kexec_load(), a buffer is allocated via vzalloc() to store elf
headers.  While it's not freed back to system when kdump kernel is
reloaded or unloaded, or when image->elf_header is successfully set and
then fails to load kdump kernel for some reason. Fix it by freeing the
buffer in arch_kimage_file_post_load_cleanup().

Fixes: 8acea455fafa ("RISC-V: Support for kexec_file on panic")
Signed-off-by: Li Huafei <lihuafei1@huawei.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20221104095658.141222-2-lihuafei1@huawei.com
Cc: stable@vger.kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/riscv/kernel/elf_kexec.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/arch/riscv/kernel/elf_kexec.c b/arch/riscv/kernel/elf_kexec.c
index ff30fcb43f47..5372b708fae2 100644
--- a/arch/riscv/kernel/elf_kexec.c
+++ b/arch/riscv/kernel/elf_kexec.c
@@ -26,6 +26,10 @@ int arch_kimage_file_post_load_cleanup(struct kimage *image)
 	kvfree(image->arch.fdt);
 	image->arch.fdt = NULL;
 
+	vfree(image->elf_headers);
+	image->elf_headers = NULL;
+	image->elf_headers_sz = 0;
+
 	return kexec_image_post_load_cleanup_default(image);
 }