Subject: + vsprintf-ignore-%n-again.patch added to -mm tree To: keescook@xxxxxxxxxxxx,davem@xxxxxxxxxxxxx,joe@xxxxxxxxxxx,penguin-kernel@xxxxxxxxxxxxxxxxxxx From: akpm@xxxxxxxxxxxxxxxxxxxx Date: Tue, 08 Oct 2013 13:30:41 -0700 The patch titled Subject: vsprintf: ignore %n again has been added to the -mm tree. Its filename is vsprintf-ignore-%n-again.patch This patch should soon appear at http://ozlabs.org/~akpm/mmots/broken-out/vsprintf-ignore-%n-again.patch and later at http://ozlabs.org/~akpm/mmotm/broken-out/vsprintf-ignore-%n-again.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Kees Cook <keescook@xxxxxxxxxxxx> Subject: vsprintf: ignore %n again This ignores %n in printf again, as was originally documented. Implementing %n poses a greater security risk than utility, so it should stay ignored. To help anyone attempting to use %n, a warning will be emitted if it is encountered. Based on an earlier patch by Joe Perches. Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx> Cc: Joe Perches <joe@xxxxxxxxxxx> Cc: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx> Cc: David Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- lib/vsprintf.c | 20 +++++++++----------- 1 file changed, 9 insertions(+), 11 deletions(-) diff -puN lib/vsprintf.c~vsprintf-ignore-%n-again lib/vsprintf.c --- a/lib/vsprintf.c~vsprintf-ignore-%n-again +++ a/lib/vsprintf.c @@ -1685,18 +1685,16 @@ int vsnprintf(char *buf, size_t size, co break; case FORMAT_TYPE_NRCHARS: { - u8 qualifier = spec.qualifier; + /* + * Since %n poses a greater security risk than + * utility, ignore %n and skip its argument. + */ + void *skip_arg; - if (qualifier == 'l') { - long *ip = va_arg(args, long *); - *ip = (str - buf); - } else if (_tolower(qualifier) == 'z') { - size_t *ip = va_arg(args, size_t *); - *ip = (str - buf); - } else { - int *ip = va_arg(args, int *); - *ip = (str - buf); - } + WARN_ONCE(1, "Please remove ignored %%n in '%s'\n", + old_fmt); + + skip_arg = va_arg(args, void *); break; } _ Patches currently in -mm which might be from keescook@xxxxxxxxxxxx are mm-avoid-increase-sizeofstruct-page-due-to-split-page-table-lock.patch mm-rename-use_split_ptlocks-to-use_split_pte_ptlocks.patch mm-convert-mm-nr_ptes-to-atomic_long_t.patch mm-introduce-api-for-split-page-table-lock-for-pmd-level.patch mm-thp-change-pmd_trans_huge_lock-to-return-taken-lock.patch mm-thp-move-ptl-taking-inside-page_check_address_pmd.patch mm-thp-do-not-access-mm-pmd_huge_pte-directly.patch mm-hugetlb-convert-hugetlbfs-to-use-split-pmd-lock.patch mm-convert-the-rest-to-new-page-table-lock-api.patch mm-implement-split-page-table-lock-for-pmd-level.patch x86-mm-enable-split-page-table-lock-for-pmd-level.patch printk-report-console-names-during-cut-over.patch kernel-printk-printkc-convert-to-pr_foo.patch seq_file-introduce-seq_setwidth-and-seq_pad.patch seq_file-remove-%n-usage-from-seq_file-users.patch vsprintf-ignore-%n-again.patch binfmt_elfc-use-get_random_int-to-fix-entropy-depleting.patch drivers-message-i2o-driverc-add-missing-destroy_workqueue-on-error-in-i2o_driver_register.patch gcov-move-gcov-structs-definitions-to-a-gcc-version-specific-file.patch gcov-add-support-for-gcc-47-gcov-format.patch gcov-compile-specific-gcov-implementation-based-on-gcc-version.patch kernel-add-support-for-init_array-constructors.patch kernel-add-support-for-init_array-constructors-fix.patch kernel-gcov-fsc-use-pr_warn.patch linux-next.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html