Date: Sun, 11 Feb 2024 03:39:20 GMT From: Konstantin Belousov <kib@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: 29d4f8bfc642 - main - ELF note parser: provide more info on failure Message-ID: <202402110339.41B3dKCj060173@gitrepo.freebsd.org>
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The branch main has been updated by kib: URL: https://cgit.FreeBSD.org/src/commit/?id=29d4f8bfc642f0196c27eb469ea7eb326ff529d1 commit 29d4f8bfc642f0196c27eb469ea7eb326ff529d1 Author: Konstantin Belousov <kib@FreeBSD.org> AuthorDate: 2024-02-10 01:36:58 +0000 Commit: Konstantin Belousov <kib@FreeBSD.org> CommitDate: 2024-02-11 03:37:12 +0000 ELF note parser: provide more info on failure Print reasons when parser declined to parse notes, due to mis-alignment, invalid length, or too many notes (the later typically means that there is a loop). Also increase the loop limit to 4096, which gives enough iterations for notes to fill whole notes' page. Sponsored by: The FreeBSD Foundation MFC after: 3 days --- sys/kern/imgact_elf.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/sys/kern/imgact_elf.c b/sys/kern/imgact_elf.c index 49dcae050d76..8f85a4f5e18a 100644 --- a/sys/kern/imgact_elf.c +++ b/sys/kern/imgact_elf.c @@ -2709,6 +2709,7 @@ __elfN(note_procstat_auxv)(void *arg, struct sbuf *sb, size_t *sizep) } } +#define MAX_NOTES_LOOP 4096 bool __elfN(parse_notes)(struct image_params *imgp, Elf_Note *checknote, const char *note_vendor, const Elf_Phdr *pnote, @@ -2748,9 +2749,15 @@ __elfN(parse_notes)(struct image_params *imgp, Elf_Note *checknote, pnote->p_offset + pnote->p_filesz); buf = NULL; } - for (i = 0; i < 100 && note >= note0 && note < note_end; i++) { - if (!aligned(note, Elf32_Addr) || (const char *)note_end - - (const char *)note < sizeof(Elf_Note)) { + for (i = 0; i < MAX_NOTES_LOOP && note >= note0 && note < note_end; + i++) { + if (!aligned(note, Elf32_Addr)) { + uprintf("Unaligned ELF note\n"); + goto retf; + } + if ((const char *)note_end - (const char *)note < + sizeof(Elf_Note)) { + uprintf("ELF note to short\n"); goto retf; } if (note->n_namesz != checknote->n_namesz || @@ -2770,6 +2777,8 @@ nextnote: roundup2(note->n_namesz, ELF_NOTE_ROUNDSIZE) + roundup2(note->n_descsz, ELF_NOTE_ROUNDSIZE)); } + if (i >= MAX_NOTES_LOOP) + uprintf("ELF note parser reached %d notes\n", i); retf: res = false; ret:
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