On Wed, Jul 24, 2024 at 03:52:02PM -0700, Andrii Nakryiko wrote: > 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 <adobriyan@xxxxxxxxx> > Signed-off-by: Andrii Nakryiko <andrii@xxxxxxxxxx> looks like this one never got in right? https://lore.kernel.org/bpf/CAEf4BzaAKAwO=-=0qZQfkHhBodN0MQUHpL-RY7tCHdcFidjv-Q@xxxxxxxxxxxxxx/ I couldn't find the place where you remove that check ;-) jirka > --- > 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; > > -- > 2.43.0 > >
