From: Thorsten Blum <thorsten.blum@linux.dev>
To: Borislav Petkov <bp@alien8.de>
Cc: Thomas Gleixner <tglx@kernel.org>, Ingo Molnar <mingo@redhat.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
Chao Fan <fanc.fnst@cn.fujitsu.com>,
stable@vger.kernel.org, Borislav Petkov <bp@suse.de>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] x86/boot: Reject truncated acpi_rsdp= values
Date: Thu, 18 Jun 2026 19:59:09 +0200 [thread overview]
Message-ID: <ajQx7dBWRuRFuKwE@linux.dev> (raw)
In-Reply-To: <20260618163856.GAajQfIDh0s31VINiS@fat_crate.local>
On Thu, Jun 18, 2026 at 09:38:56AM -0700, Borislav Petkov wrote:
> On Thu, Jun 18, 2026 at 05:03:46PM +0200, Thorsten Blum wrote:
> > get_cmdline_acpi_rsdp() can truncate it into a different, parseable
> > address and use that instead.
>
> How?
The buffer has 19 bytes to hold the "0x" prefix, 16 hex digits, and the
NUL terminator.
cmdline_find_option() copies only bufsize - 1 bytes, but returns the
full argument length. So for example:
acpi_rsdp=0x0123456789abcdefx
gets copied as:
0x0123456789abcdef
which boot_kstrtoul() parses successfully. The user supplied an invalid
value, but we silently use the truncated prefix as the RSDP address.
next prev parent reply other threads:[~2026-06-18 17:59 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-17 13:04 [PATCH] x86/boot: Reject truncated acpi_rsdp= values Thorsten Blum
2026-06-18 4:54 ` Borislav Petkov
2026-06-18 15:03 ` Thorsten Blum
2026-06-18 16:38 ` Borislav Petkov
2026-06-18 17:59 ` Thorsten Blum [this message]
2026-06-18 18:04 ` Borislav Petkov
2026-06-18 18:57 ` Thorsten Blum
2026-06-18 19:34 ` Borislav Petkov
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