[PATCH v3 1/2] kexec: return -ENOEXEC from image probe functions on mismatch

[Mukesh Pilaniya <mpilaniy@redhat.com>]

Several kexec_file_load() image probe functions return -EINVAL when
they do not recognize the image format.  A probe function that rejects
an image should return -ENOEXEC to indicate that the image is not a
recognized executable format.  -EINVAL implies a problem with the
syscall parameters, not with image recognition.

kexec_image_probe_default() iterates through registered loaders and
returns the last probe's error code to the caller.  That error
propagates as the kexec_file_load() return value to userspace.
Returning -EINVAL from a probe when no loader matches is semantically
incorrect and misleads userspace about the nature of the failure.

Return -ENOEXEC from all probe functions and their helpers when the
image format is not recognized.

Signed-off-by: Mukesh Pilaniya <mpilaniy@redhat.com>
Reviewed-by: Philipp Rudo <prudo@redhat.com>
Reviewed-by: Pratyush Yadav <pratyush@kernel.org>
Reviewed-by: Bradley Morgan <include@grrlz.net>
---
 arch/arm64/kernel/kexec_image.c   | 4 ++--
 arch/loongarch/kernel/kexec_efi.c | 4 ++--
 arch/riscv/kernel/kexec_image.c   | 4 ++--
 kernel/kexec_elf.c                | 4 ++--
 4 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/arch/arm64/kernel/kexec_image.c b/arch/arm64/kernel/kexec_image.c
index b70f4df15a1a..101259874d44 100644
--- a/arch/arm64/kernel/kexec_image.c
+++ b/arch/arm64/kernel/kexec_image.c
@@ -25,10 +25,10 @@ static int image_probe(const char *kernel_buf, unsigned long kernel_len)
 		(const struct arm64_image_header *)(kernel_buf);
 
 	if (!h || (kernel_len < sizeof(*h)))
-		return -EINVAL;
+		return -ENOEXEC;
 
 	if (memcmp(&h->magic, ARM64_IMAGE_MAGIC, sizeof(h->magic)))
-		return -EINVAL;
+		return -ENOEXEC;
 
 	return 0;
 }
diff --git a/arch/loongarch/kernel/kexec_efi.c b/arch/loongarch/kernel/kexec_efi.c
index 5ee78ebb1546..28a1d0420ba3 100644
--- a/arch/loongarch/kernel/kexec_efi.c
+++ b/arch/loongarch/kernel/kexec_efi.c
@@ -24,12 +24,12 @@ static int efi_kexec_probe(const char *kernel_buf, unsigned long kernel_len)
 
 	if (!h || (kernel_len < sizeof(*h))) {
 		kexec_dprintk("No LoongArch image header.\n");
-		return -EINVAL;
+		return -ENOEXEC;
 	}
 
 	if (!loongarch_header_check_dos_sig(h)) {
 		kexec_dprintk("No LoongArch PE image header.\n");
-		return -EINVAL;
+		return -ENOEXEC;
 	}
 
 	return 0;
diff --git a/arch/riscv/kernel/kexec_image.c b/arch/riscv/kernel/kexec_image.c
index 51dc89259f16..963a25f5b55b 100644
--- a/arch/riscv/kernel/kexec_image.c
+++ b/arch/riscv/kernel/kexec_image.c
@@ -20,7 +20,7 @@ static int image_probe(const char *kernel_buf, unsigned long kernel_len)
 	const struct riscv_image_header *h = (const struct riscv_image_header *)kernel_buf;
 
 	if (!h || kernel_len < sizeof(*h))
-		return -EINVAL;
+		return -ENOEXEC;
 
 	/* According to Documentation/arch/riscv/boot-image-header.rst,
 	 * use "magic2" field to check when version >= 0.2.
@@ -28,7 +28,7 @@ static int image_probe(const char *kernel_buf, unsigned long kernel_len)
 
 	if (h->version >= RISCV_HEADER_VERSION &&
 	    memcmp(&h->magic2, RISCV_IMAGE_MAGIC2, sizeof(h->magic2)))
-		return -EINVAL;
+		return -ENOEXEC;
 
 	return 0;
 }
diff --git a/kernel/kexec_elf.c b/kernel/kexec_elf.c
index 3a5c25b2adc9..89a444a00693 100644
--- a/kernel/kexec_elf.c
+++ b/kernel/kexec_elf.c
@@ -172,7 +172,7 @@ static int elf_read_ehdr(const char *buf, size_t len, struct elfhdr *ehdr)
 
 	default:
 		pr_debug("Unknown ELF class.\n");
-		return -EINVAL;
+		return -ENOEXEC;
 	}
 
 	return elf_is_ehdr_sane(ehdr, len) ? 0 : -ENOEXEC;
@@ -236,7 +236,7 @@ static int elf_read_phdr(const char *buf, size_t len,
 
 	default:
 		pr_debug("Unknown ELF class.\n");
-		return -EINVAL;
+		return -ENOEXEC;
 	}
 
 	return elf_is_phdr_sane(phdr, len) ? 0 : -ENOEXEC;

-- 
Git-155)