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linux-user: Fix parse_elf_properties GNU0_MAGIC check

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Comparing a string of 4 bytes only works in little-endian.

Adjust bulk bswap to only apply to the note payload.
Perform swapping of the note header manually; the magic
is defined so that it does not need a runtime swap.

Fixes: 83f990eb5a ("linux-user/elfload: Parse NT_GNU_PROPERTY_TYPE_0 notes")
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2596
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Michael Tokarev <mjt@tls.msk.ru>
This commit is contained in:
Richard Henderson 2024-10-05 09:01:22 -07:00
parent a9ee641bd4
commit 2884596f5f
1 changed files with 6 additions and 6 deletions
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12
linux-user/elfload.c
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@ -3121,11 +3121,11 @@ static bool parse_elf_properties(const ImageSource *src,
}
/*
* The contents of a valid PT_GNU_PROPERTY is a sequence
* of uint32_t -- swap them all now.
* The contents of a valid PT_GNU_PROPERTY is a sequence of uint32_t.
* Swap most of them now, beyond the header and namesz.
*/
#ifdef BSWAP_NEEDED
for (int i = 0; i < n / 4; i++) {
for (int i = 4; i < n / 4; i++) {
bswap32s(note.data + i);
}
#endif
@ -3135,15 +3135,15 @@ static bool parse_elf_properties(const ImageSource *src,
* immediately follows nhdr and is thus at the 4th word. Further, all
* of the inputs to the kernel's round_up are multiples of 4.
*/
if (note.nhdr.n_type != NT_GNU_PROPERTY_TYPE_0 ||
note.nhdr.n_namesz != NOTE_NAME_SZ ||
if (tswap32(note.nhdr.n_type) != NT_GNU_PROPERTY_TYPE_0 ||
tswap32(note.nhdr.n_namesz) != NOTE_NAME_SZ ||
note.data[3] != GNU0_MAGIC) {
error_setg(errp, "Invalid note in PT_GNU_PROPERTY");
return false;
}
off = sizeof(note.nhdr) + NOTE_NAME_SZ;
datasz = note.nhdr.n_descsz + off;
datasz = tswap32(note.nhdr.n_descsz) + off;
if (datasz > n) {
error_setg(errp, "Invalid note size in PT_GNU_PROPERTY");
return false;