Since ELF notes need to be properly aligned they can include padding. Make sure the padding itself and the padding calculation doesn't overflow. Signed-off-by: Mark Wielaard --- libelf/ChangeLog | 4 ++++ libelf/gelf_getnote.c | 9 +++++++-- 2 files changed, 11 insertions(+), 2 deletions(-) diff --git a/libelf/ChangeLog b/libelf/ChangeLog index 4886093..beb431f 100644 --- a/libelf/ChangeLog +++ b/libelf/ChangeLog @@ -1,5 +1,9 @@ 2014-11-16 Mark Wielaard + * gelf_getnote.c (gelf_getnote): Check padding overflow. + +2014-11-16 Mark Wielaard + * elf_getdata.c (__libelf_set_rawdata_wrlock): Declare offset, size and align as Elf64_Off and Elf64_Xword not size_t. diff --git a/libelf/gelf_getnote.c b/libelf/gelf_getnote.c index 8bb78c1..7dc8215 100644 --- a/libelf/gelf_getnote.c +++ b/libelf/gelf_getnote.c @@ -73,16 +73,21 @@ gelf_getnote (data, offset, result, name_offset, desc_offset) const GElf_Nhdr *n = data->d_buf + offset; offset += sizeof *n; + /* Include padding. Check below for overflow. */ GElf_Word namesz = NOTE_ALIGN (n->n_namesz); GElf_Word descsz = NOTE_ALIGN (n->n_descsz); - if (unlikely (data->d_size - offset < namesz)) + if (unlikely (offset > data->d_size + || data->d_size - offset < namesz + || (namesz == 0 && n->n_namesz != 0))) offset = 0; else { *name_offset = offset; offset += namesz; - if (unlikely (data->d_size - offset < descsz)) + if (unlikely (offset > data->d_size + || data->d_size - offset < descsz + || (descsz == 0 && n->n_descsz != 0))) offset = 0; else { -- 1.8.3.1