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Tue, 9 Jul 2024 20:42:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1720557778; bh=C6pZlI4b95ZXtBjMHdytNmZo2a2DbuYqAFHnzJFYuwM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=uymoLYG0Q9SwCI7KQesqLBFvnArB0/gIUKz3koEE36GLmnH/t6Hnm7YORfXF3TtLR UKV0yis/gKz6Xvzr4AmQRHAOOAl9ZY30qvaanFYSSOXcssDkZtWcighSgsEbkol3PC tbPi/R15irjarwVMdKzVktzp/HPknwURi5Xgo13swWH1SYajub6Hyuocw+P4Lyl7da 77OH9LrPv5JINgUMj1vVlgU0Pcdvi2WJ2ntIj8pH3+wSHEE44KzlMy/r8bAdDWXV+p BRBfzJs3zH6o0SiqpXQ+4qiMCv7zqV0iILQhHpdlRKyh8fVHhjq0M20WNBvrofiX+4 ucJ88atYNDVeg== From: Andrii Nakryiko To: bpf@vger.kernel.org Cc: linux-mm@kvack.org, akpm@linux-foundation.org, adobriyan@gmail.com, shakeel.butt@linux.dev, hannes@cmpxchg.org, ak@linux.intel.com, osandov@osandov.com, Andrii Nakryiko Subject: [PATCH bpf-next 02/10] lib/buildid: take into account e_phoff when fetching program headers Date: Tue, 9 Jul 2024 13:42:37 -0700 Message-ID: <20240709204245.3847811-3-andrii@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240709204245.3847811-1-andrii@kernel.org> References: <20240709204245.3847811-1-andrii@kernel.org> MIME-Version: 1.0 X-Rspam-User: X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: D9B60140003 X-Stat-Signature: hko9sdqxrdqoa6zou3zbzq6sqtowdraz X-HE-Tag: 1720557779-316391 X-HE-Meta: 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 4rWWT3Ua sQ/9PGkP+ZNdq04KXZUSbBwQEUZGgPUT3kLe5gzNPwd1B2HT0hw8NqBWf5MeGGw1JrfWTq37p4HNT/aIAqfPJKYpcluHZcRNjlDeOH22JpM+/K8DLi266J40aeQ6UTtEiPc25kI/9p0DL72IZA8Jsh+RMkfZ8lDuyNBmGwtYXqkSnYrizi/fCCykGm8q3DH61UJk9m6B3wKYLIdTnrO8+1tDGtE2yZm/oyXPMr4TsU6YFHSp8UMFSCx449GHrD9CVq+9LrpktxS39KbFJ3phSQXf8H3DfceGhg+OQmspfNIpP7Io3uu5CW79ZlQ== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Current code assumption is that program (segment) headers are following ELF header immediately. This is a common case, but is not guaranteed. So take into account e_phoff field of the ELF header when accessing program headers. Reported-by: Alexey Dobriyan Signed-off-by: Andrii Nakryiko --- lib/buildid.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/lib/buildid.c b/lib/buildid.c index 1442a2483a8b..ce48ffab4111 100644 --- a/lib/buildid.c +++ b/lib/buildid.c @@ -206,7 +206,7 @@ static int get_build_id_32(struct freader *r, unsigned char *build_id, __u32 *si { const Elf32_Ehdr *ehdr; const Elf32_Phdr *phdr; - __u32 phnum, i; + __u32 phnum, phoff, i; ehdr = freader_fetch(r, 0, sizeof(Elf32_Ehdr)); if (!ehdr) @@ -214,13 +214,14 @@ static int get_build_id_32(struct freader *r, unsigned char *build_id, __u32 *si /* subsequent freader_fetch() calls invalidate pointers, so remember locally */ phnum = ehdr->e_phnum; + phoff = READ_ONCE(ehdr->e_phoff); /* only supports phdr that fits in one page */ if (phnum > (PAGE_SIZE - sizeof(Elf32_Ehdr)) / sizeof(Elf32_Phdr)) return -EINVAL; for (i = 0; i < phnum; ++i) { - phdr = freader_fetch(r, i * sizeof(Elf32_Phdr), sizeof(Elf32_Phdr)); + phdr = freader_fetch(r, phoff + i * sizeof(Elf32_Phdr), sizeof(Elf32_Phdr)); if (!phdr) return r->err; @@ -237,6 +238,7 @@ static int get_build_id_64(struct freader *r, unsigned char *build_id, __u32 *si const Elf64_Ehdr *ehdr; const Elf64_Phdr *phdr; __u32 phnum, i; + __u64 phoff; ehdr = freader_fetch(r, 0, sizeof(Elf64_Ehdr)); if (!ehdr) @@ -244,13 +246,14 @@ static int get_build_id_64(struct freader *r, unsigned char *build_id, __u32 *si /* subsequent freader_fetch() calls invalidate pointers, so remember locally */ phnum = ehdr->e_phnum; + phoff = READ_ONCE(ehdr->e_phoff); /* only supports phdr that fits in one page */ if (phnum > (PAGE_SIZE - sizeof(Elf64_Ehdr)) / sizeof(Elf64_Phdr)) return -EINVAL; for (i = 0; i < phnum; ++i) { - phdr = freader_fetch(r, i * sizeof(Elf64_Phdr), sizeof(Elf64_Phdr)); + phdr = freader_fetch(r, phoff + i * sizeof(Elf64_Phdr), sizeof(Elf64_Phdr)); if (!phdr) return r->err;