Date: Sun, 12 Mar 2017 14:31:17 -0500 From: Pedro Giffuni <pfg@FreeBSD.org> To: Ian Lepore <ian@freebsd.org>, Lawrence Stewart <lstewart@freebsd.org>, src-committers@freebsd.org, =?UTF-8?Q?Dag-Erling_Sm=c3=b8rgrav?= <des@des.no>, svn-src-head@freebsd.org Subject: Re: svn commit: r314780 - head/lib/libpam/modules/pam_exec Message-ID: <374fa6f7-9e02-7c50-ccde-7f2c5386123e@FreeBSD.org> In-Reply-To: <1489341856.40576.88.camel@freebsd.org> References: <201703061545.v26FjkNI027057@repo.freebsd.org> <739617a4-3eed-28d1-73e4-86d25d6d5fed@freebsd.org> <1839903b-fb05-bf3f-17bb-697afca9ecb7@FreeBSD.org> <1489341856.40576.88.camel@freebsd.org>
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On 3/12/2017 1:04 PM, Ian Lepore wrote: > On Sun, 2017-03-12 at 12:30 -0500, Pedro Giffuni wrote: >> On 3/12/2017 12:14 PM, Lawrence Stewart wrote: >>> Hi Pedro, >>> >>> On 07/03/2017 02:45, Pedro F. Giffuni wrote: >>>> Author: pfg >>>> Date: Mon Mar 6 15:45:46 2017 >>>> New Revision: 314780 >>>> URL: https://svnweb.freebsd.org/changeset/base/314780 >>>> >>>> Log: >>>> libpam: extra bounds checking through reallocarray(3). >>>> >>>> Reviewed by: des >>>> MFC after: 1 week >>>> >>>> Modified: >>>> head/lib/libpam/modules/pam_exec/pam_exec.c >>>> >>>> Modified: head/lib/libpam/modules/pam_exec/pam_exec.c >>>> ================================================================= >>>> ============= >>>> --- head/lib/libpam/modules/pam_exec/pam_exec.c Mon Mar 6 >>>> 15:42:03 2017 (r314779) >>>> +++ head/lib/libpam/modules/pam_exec/pam_exec.c Mon Mar 6 >>>> 15:45:46 2017 (r314780) >>>> @@ -138,7 +138,7 @@ _pam_exec(pam_handle_t *pamh __unused, >>>> nitems = sizeof(env_items) / sizeof(*env_items); >>>> /* Count PAM return values put in the environment. */ >>>> nitems_rv = options->return_prog_exit_status ? >>>> PAM_RV_COUNT : 0; >>>> - tmp = realloc(envlist, (envlen + nitems + 1 + nitems_rv >>>> + 1) * >>>> + tmp = reallocarray(envlist, envlen + nitems + 1 + >>>> nitems_rv + 1, >>>> sizeof(*envlist)); >>>> if (tmp == NULL) { >>>> openpam_free_envlist(envlist); >>>> >>> This commit breaks pam_exec for me... without this change I see the >>> expected PAM_* environment variables from my execed script, but >>> with >>> this change I no longer see any of them. >> Thanks for the report. >> >> It seems strange this can cause any failure. Perhaps there is a >> latent >> overflow here and we have been living with it? I will revert while it >> is >> investigated. >> >> BTW, the "nitems" variable may conflict with nitems() in sys/param.h. >> > A quirk of C that's often forgotten is that a function-like macro is > only expanded as a macro if the token following the macro name is an > open paren. So nitems() is a macro invokation and nitems = 0; is just > a variable. > > I'm not arguing against the replacement of variables named nitems, I > actually think that should have been done as part of importing the > function-like definition of nitems from netbsd. I am not worried about 'nitems', which is actually FreeBSD-native (NetBSD has another name for it). I do think reallocarray() found an underlying issue here though. Pedro.
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