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From: Giacomo Mazzola <gmazz@amazon.de>
To: <kvm@vger.kernel.org>
Cc: Giacomo Mazzola <gmazz@amazon.de>
Subject: [kvm-unit-tests PATCH 7/8] efi: fix load_options_size conversion to character count
Date: Tue, 9 Jun 2026 14:08:59 +0000	[thread overview]
Message-ID: <20260609140901.95727-8-gmazz@amazon.de> (raw)
In-Reply-To: <20260609140901.95727-1-gmazz@amazon.de>

load_options_size is in bytes, but options_chars is used as the
iteration count over the u16 load options array.  Divide by
sizeof(u16) to convert from bytes to UTF-16 code units; without
this, the loop reads past the end of the load options buffer.

The original Linux kernel code (drivers/firmware/efi/libstub/
efi-stub-helper.c) from which this function was adapted performs
the same conversion:

    options_chars = options_size / sizeof(efi_char16_t);

This was lost when the function was ported to KUT.

Fixes: 85c3c524 ("lib/efi: Add support for getting the cmdline")
Signed-off-by: Giacomo Mazzola <gmazz@amazon.de>
---
 lib/efi.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/efi.c b/lib/efi.c
index f396bd71..d1be2bfc 100644
--- a/lib/efi.c
+++ b/lib/efi.c
@@ -134,7 +134,7 @@ static char *efi_convert_cmdline(struct efi_loaded_image_64 *image, int *cmd_lin
 {
 	const u16 *s2;
 	unsigned long cmdline_addr = 0;
-	int options_chars = image->load_options_size;
+	int options_chars = image->load_options_size / sizeof(u16);
 	const u16 *options = image->load_options;
 	int options_bytes = 0, safe_options_bytes = 0;  /* UTF-8 bytes */
 	bool in_quote = false;
-- 
2.47.3




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  parent reply	other threads:[~2026-06-09 14:13 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-06-09 14:08 [kvm-unit-tests PATCH 0/8] x86: fixes for running KUT as EFI on non-QEMU KVM hosts Giacomo Mazzola
2026-06-09 14:08 ` [kvm-unit-tests PATCH 1/8] x86: efi: use PER_CPU_SIZE for per-CPU stack allocation Giacomo Mazzola
2026-06-09 14:08 ` [kvm-unit-tests PATCH 2/8] x86: fix EFI memory allocator to clamp regions to 4 GiB Giacomo Mazzola
2026-06-09 14:08 ` [kvm-unit-tests PATCH 3/8] x86: skip PMU init when no PMU is advertised Giacomo Mazzola
2026-06-09 14:08 ` [kvm-unit-tests PATCH 4/8] x86: fix ISR thunk to use absolute indirect jump Giacomo Mazzola
2026-06-09 14:08 ` [kvm-unit-tests PATCH 5/8] x86: replace per-AP bringup prints with a single summary line Giacomo Mazzola
2026-06-09 14:08 ` [kvm-unit-tests PATCH 6/8] x86: add timeout-based SMP bringup when fw_cfg is unavailable Giacomo Mazzola
2026-06-09 14:08 ` Giacomo Mazzola [this message]
2026-06-10 16:09   ` [kvm-unit-tests PATCH 7/8] efi: fix load_options_size conversion to character count Andrew Jones
2026-06-09 14:09 ` [kvm-unit-tests PATCH 8/8] efi: parse KUT_ENV= from load options into environ Giacomo Mazzola
2026-06-10 18:18   ` Andrew Jones
2026-06-25 14:04   ` [kvm-unit-tests PATCH v2 8/8] lib: parse KUT_ENV= from command line " Giacomo Mazzola

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