From patchwork Tue Oct 12 16:16:27 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Siddhesh Poyarekar X-Patchwork-Id: 46138 X-Patchwork-Delegate: azanella@linux.vnet.ibm.com Return-Path: X-Original-To: patchwork@sourceware.org Delivered-To: patchwork@sourceware.org Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 719683857430 for ; Tue, 12 Oct 2021 16:17:47 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 719683857430 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1634055467; bh=n8Pch/h1oV8u7yHKOhjzPLRIXs4I2CoB0UZk7n9QYug=; h=To:Subject:Date:In-Reply-To:References:List-Id:List-Unsubscribe: List-Archive:List-Post:List-Help:List-Subscribe:From:Reply-To: From; b=oh6dGyqc3rIIlcdHpfgLUUGPhYecSQ5hZ0ujQU9CRwdNxjDq8s+VfUAgrtPxnjjgA /MMCe6dlQaDrOCcMBCxl4pavWZ0xq2x/q4OKic/kLE/8CW4/RYn0FKPoH4jLZbgF05 cPyM0MvFAHsjFxl5CplSuRTgsyLcozKV1MdM4DKs= X-Original-To: libc-alpha@sourceware.org Delivered-To: libc-alpha@sourceware.org Received: from brown.birch.relay.mailchannels.net (brown.birch.relay.mailchannels.net [23.83.209.23]) by sourceware.org (Postfix) with ESMTPS id CAC9E385743E for ; Tue, 12 Oct 2021 16:16:48 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org CAC9E385743E X-Sender-Id: dreamhost|x-authsender|siddhesh@gotplt.org Received: from relay.mailchannels.net (localhost [127.0.0.1]) by relay.mailchannels.net (Postfix) with ESMTP id BB829542879; Tue, 12 Oct 2021 16:16:43 +0000 (UTC) Received: from pdx1-sub0-mail-a74.g.dreamhost.com (100-96-18-141.trex.outbound.svc.cluster.local [100.96.18.141]) (Authenticated sender: dreamhost) by relay.mailchannels.net (Postfix) with ESMTPA id F12CB5428D5; Tue, 12 Oct 2021 16:16:42 +0000 (UTC) X-Sender-Id: dreamhost|x-authsender|siddhesh@gotplt.org Received: from pdx1-sub0-mail-a74.g.dreamhost.com (pop.dreamhost.com [64.90.62.162]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384) by 100.96.18.141 (trex/6.4.3); Tue, 12 Oct 2021 16:16:43 +0000 X-MC-Relay: Junk X-MailChannels-SenderId: dreamhost|x-authsender|siddhesh@gotplt.org X-MailChannels-Auth-Id: dreamhost X-Wiry-Quick: 6c3a5c6c00222f65_1634055403259_1095060635 X-MC-Loop-Signature: 1634055403259:3193917322 X-MC-Ingress-Time: 1634055403259 Received: from pdx1-sub0-mail-a74.g.dreamhost.com (localhost [127.0.0.1]) by pdx1-sub0-mail-a74.g.dreamhost.com (Postfix) with ESMTP id 7BCA384141; Tue, 12 Oct 2021 09:16:42 -0700 (PDT) Received: from rhbox.redhat.com (unknown [1.186.121.188]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) (Authenticated sender: siddhesh@gotplt.org) by pdx1-sub0-mail-a74.g.dreamhost.com (Postfix) with ESMTPSA id 325CC7F5CA; Tue, 12 Oct 2021 09:16:39 -0700 (PDT) X-DH-BACKEND: pdx1-sub0-mail-a74 To: libc-alpha@sourceware.org Subject: [PATCH 1/3] Don't add access size hints to fortifiable functions Date: Tue, 12 Oct 2021 21:46:27 +0530 Message-Id: <20211012161629.302696-2-siddhesh@sourceware.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20211012161629.302696-1-siddhesh@sourceware.org> References: <20211012161629.302696-1-siddhesh@sourceware.org> MIME-Version: 1.0 X-Spam-Status: No, score=-3494.6 required=5.0 tests=BAYES_00, GIT_PATCH_0, JMQ_SPF_NEUTRAL, KAM_DMARC_NONE, KAM_DMARC_STATUS, RCVD_IN_BARRACUDACENTRAL, RCVD_IN_DNSWL_NONE, RCVD_IN_MSPIKE_H2, RCVD_IN_SBL, SPF_HELO_NONE, SPF_NEUTRAL, TXREP autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-Patchwork-Original-From: Siddhesh Poyarekar via Libc-alpha From: Siddhesh Poyarekar Reply-To: Siddhesh Poyarekar Errors-To: libc-alpha-bounces+patchwork=sourceware.org@sourceware.org Sender: "Libc-alpha" In the context of a function definition, the size hints imply that the size of an object pointed to by one parameter is another parameter. This doesn't make sense for the fortified versions of the functions since that's the bit it's trying to validate. This is harmless with __builtin_object_size since it has fairly simple semantics when it comes to objects passed as function parameters. With __builtin_dynamic_object_size we could (as my patchset for gcc[1] already does) use the access attribute to determine the object size in the general case but it misleads the fortified functions. Disable the access attribute for fortified function inline functions when building at _FORTIFY_SOURCE=3 to make this work better. The access attributes remain for the _chk variants since they can be used by the compiler to warn when the caller is passing invalid arguments. Signed-off-by: Siddhesh Poyarekar Reviewed-by: Adhemerval Zanella --- io/bits/poll2.h | 4 ++-- io/sys/poll.h | 6 +++--- libio/bits/stdio2.h | 4 ++-- libio/stdio.h | 4 ++-- misc/sys/cdefs.h | 10 ++++++++++ posix/unistd.h | 28 ++++++++++++++++------------ stdlib/stdlib.h | 5 +++-- string/bits/string_fortified.h | 5 +++-- string/string.h | 2 +- 9 files changed, 42 insertions(+), 26 deletions(-) diff --git a/io/bits/poll2.h b/io/bits/poll2.h index a623678c09..be74d020f2 100644 --- a/io/bits/poll2.h +++ b/io/bits/poll2.h @@ -33,7 +33,7 @@ extern int __REDIRECT (__poll_chk_warn, (struct pollfd *__fds, nfds_t __nfds, __poll_chk) __warnattr ("poll called with fds buffer too small file nfds entries"); -__fortify_function __attr_access ((__write_only__, 1, 2)) int +__fortify_function __fortified_attr_access (__write_only__, 1, 2) int poll (struct pollfd *__fds, nfds_t __nfds, int __timeout) { if (__glibc_objsize (__fds) != (__SIZE_TYPE__) -1) @@ -64,7 +64,7 @@ extern int __REDIRECT (__ppoll_chk_warn, (struct pollfd *__fds, nfds_t __nfds, __ppoll_chk) __warnattr ("ppoll called with fds buffer too small file nfds entries"); -__fortify_function __attr_access ((__write_only__, 1, 2)) int +__fortify_function __fortified_attr_access (__write_only__, 1, 2) int ppoll (struct pollfd *__fds, nfds_t __nfds, const struct timespec *__timeout, const __sigset_t *__ss) { diff --git a/io/sys/poll.h b/io/sys/poll.h index e640efb2bc..751c7f5f72 100644 --- a/io/sys/poll.h +++ b/io/sys/poll.h @@ -52,7 +52,7 @@ __BEGIN_DECLS This function is a cancellation point and therefore not marked with __THROW. */ extern int poll (struct pollfd *__fds, nfds_t __nfds, int __timeout) - __attr_access ((__write_only__, 1, 2)); + __fortified_attr_access (__write_only__, 1, 2); #ifdef __USE_GNU /* Like poll, but before waiting the threads signal mask is replaced @@ -64,7 +64,7 @@ extern int poll (struct pollfd *__fds, nfds_t __nfds, int __timeout) extern int ppoll (struct pollfd *__fds, nfds_t __nfds, const struct timespec *__timeout, const __sigset_t *__ss) - __attr_access ((__write_only__, 1, 2)); + __fortified_attr_access (__write_only__, 1, 2); # ifdef __USE_TIME_BITS64 # ifdef __REDIRECT @@ -72,7 +72,7 @@ extern int __REDIRECT (ppoll, (struct pollfd *__fds, nfds_t __nfds, const struct timespec *__timeout, const __sigset_t *__ss), __ppoll64) - __attr_access ((__write_only__, 1, 2)); + __fortified_attr_access (__write_only__, 1, 2); # else # define ppoll __ppoll64 # endif diff --git a/libio/bits/stdio2.h b/libio/bits/stdio2.h index 3f0cab1254..4f016a5638 100644 --- a/libio/bits/stdio2.h +++ b/libio/bits/stdio2.h @@ -258,7 +258,7 @@ extern char *__REDIRECT (__fgets_chk_warn, __wur __warnattr ("fgets called with bigger size than length " "of destination buffer"); -__fortify_function __wur __attr_access ((__write_only__, 1, 2)) char * +__fortify_function __wur __fortified_attr_access (__write_only__, 1, 2) char * fgets (char *__restrict __s, int __n, FILE *__restrict __stream) { if (__glibc_objsize (__s) != (size_t) -1) @@ -320,7 +320,7 @@ extern char *__REDIRECT (__fgets_unlocked_chk_warn, __wur __warnattr ("fgets_unlocked called with bigger size than length " "of destination buffer"); -__fortify_function __wur __attr_access ((__write_only__, 1, 2)) char * +__fortify_function __wur __fortified_attr_access (__write_only__, 1, 2) char * fgets_unlocked (char *__restrict __s, int __n, FILE *__restrict __stream) { if (__glibc_objsize (__s) != (size_t) -1) diff --git a/libio/stdio.h b/libio/stdio.h index 0a5c76b552..f208f5ef79 100644 --- a/libio/stdio.h +++ b/libio/stdio.h @@ -590,7 +590,7 @@ extern int putw (int __w, FILE *__stream); This function is a possible cancellation point and therefore not marked with __THROW. */ extern char *fgets (char *__restrict __s, int __n, FILE *__restrict __stream) - __wur __attr_access ((__write_only__, 1, 2)); + __wur __fortified_attr_access (__write_only__, 1, 2); #if __GLIBC_USE (DEPRECATED_GETS) /* Get a newline-terminated string from stdin, removing the newline. @@ -614,7 +614,7 @@ extern char *gets (char *__s) __wur __attribute_deprecated__; therefore not marked with __THROW. */ extern char *fgets_unlocked (char *__restrict __s, int __n, FILE *__restrict __stream) __wur - __attr_access ((__write_only__, 1, 2)); + __fortified_attr_access (__write_only__, 1, 2); #endif diff --git a/misc/sys/cdefs.h b/misc/sys/cdefs.h index c8e10aae17..d08c2adfd0 100644 --- a/misc/sys/cdefs.h +++ b/misc/sys/cdefs.h @@ -606,12 +606,22 @@ _Static_assert (0, "IEEE 128-bits long double requires redirection on this platf size-index is not provided: access (access-mode, [, ]) */ # define __attr_access(x) __attribute__ ((__access__ x)) +/* For _FORTIFY_SOURCE == 3 we use __builtin_dynamic_object_size, which may + use the access attribute to get object sizes from function definition + arguments, so we can't use them on functions we fortify. Drop the object + size hints for such functions. */ +# if __USE_FORTIFY_LEVEL == 3 +# define __fortified_attr_access(a, o, s) __attribute__ ((__access__ (a, o))) +# else +# define __fortified_attr_access(a, o, s) __attr_access ((a, o, s)) +# endif # if __GNUC_PREREQ (11, 0) # define __attr_access_none(argno) __attribute__ ((__access__ (__none__, argno))) # else # define __attr_access_none(argno) # endif #else +# define __fortified_attr_access(a, o, s) # define __attr_access(x) # define __attr_access_none(argno) #endif diff --git a/posix/unistd.h b/posix/unistd.h index 8224c5fbc9..7a61ff5e86 100644 --- a/posix/unistd.h +++ b/posix/unistd.h @@ -369,7 +369,7 @@ extern void closefrom (int __lowfd) __THROW; This function is a cancellation point and therefore not marked with __THROW. */ extern ssize_t read (int __fd, void *__buf, size_t __nbytes) __wur - __attr_access ((__write_only__, 2, 3)); + __fortified_attr_access (__write_only__, 2, 3); /* Write N bytes of BUF to FD. Return the number written, or -1. @@ -388,7 +388,7 @@ extern ssize_t write (int __fd, const void *__buf, size_t __n) __wur __THROW. */ extern ssize_t pread (int __fd, void *__buf, size_t __nbytes, __off_t __offset) __wur - __attr_access ((__write_only__, 2, 3)); + __fortified_attr_access (__write_only__, 2, 3); /* Write N bytes of BUF to FD at the given position OFFSET without changing the file pointer. Return the number written, or -1. @@ -404,7 +404,7 @@ extern ssize_t pwrite (int __fd, const void *__buf, size_t __n, extern ssize_t __REDIRECT (pread, (int __fd, void *__buf, size_t __nbytes, __off64_t __offset), pread64) __wur - __attr_access ((__write_only__, 2, 3)); + __fortified_attr_access (__write_only__, 2, 3); extern ssize_t __REDIRECT (pwrite, (int __fd, const void *__buf, size_t __nbytes, __off64_t __offset), pwrite64) __wur @@ -421,7 +421,7 @@ extern ssize_t __REDIRECT (pwrite, (int __fd, const void *__buf, or 0 for EOF. */ extern ssize_t pread64 (int __fd, void *__buf, size_t __nbytes, __off64_t __offset) __wur - __attr_access ((__write_only__, 2, 3)); + __fortified_attr_access (__write_only__, 2, 3); /* Write N bytes of BUF to FD at the given position OFFSET without changing the file pointer. Return the number written, or -1. */ extern ssize_t pwrite64 (int __fd, const void *__buf, size_t __n, @@ -642,7 +642,7 @@ extern long int sysconf (int __name) __THROW; #ifdef __USE_POSIX2 /* Get the value of the string-valued system variable NAME. */ extern size_t confstr (int __name, char *__buf, size_t __len) __THROW - __attr_access ((__write_only__, 2, 3)); + __fortified_attr_access (__write_only__, 2, 3); #endif @@ -709,7 +709,7 @@ extern __gid_t getegid (void) __THROW; the calling process is in. Otherwise, fill in the group IDs of its supplementary groups in LIST and return the number written. */ extern int getgroups (int __size, __gid_t __list[]) __THROW __wur - __attr_access ((__write_only__, 2, 1)); + __fortified_attr_access (__write_only__, 2, 1); #ifdef __USE_GNU /* Return nonzero iff the calling process is in group GID. */ extern int group_member (__gid_t __gid) __THROW; @@ -801,7 +801,8 @@ extern char *ttyname (int __fd) __THROW; /* Store at most BUFLEN characters of the pathname of the terminal FD is open on in BUF. Return 0 on success, otherwise an error number. */ extern int ttyname_r (int __fd, char *__buf, size_t __buflen) - __THROW __nonnull ((2)) __wur __attr_access ((__write_only__, 2, 3)); + __THROW __nonnull ((2)) __wur + __fortified_attr_access (__write_only__, 2, 3); /* Return 1 if FD is a valid descriptor associated with a terminal, zero if not. */ @@ -836,7 +837,8 @@ extern int symlink (const char *__from, const char *__to) Returns the number of characters read, or -1 for errors. */ extern ssize_t readlink (const char *__restrict __path, char *__restrict __buf, size_t __len) - __THROW __nonnull ((1, 2)) __wur __attr_access ((__write_only__, 2, 3)); + __THROW __nonnull ((1, 2)) __wur + __fortified_attr_access (__write_only__, 2, 3); #endif /* Use POSIX.1-2001. */ @@ -848,7 +850,8 @@ extern int symlinkat (const char *__from, int __tofd, /* Like readlink but a relative PATH is interpreted relative to FD. */ extern ssize_t readlinkat (int __fd, const char *__restrict __path, char *__restrict __buf, size_t __len) - __THROW __nonnull ((2, 3)) __wur __attr_access ((__write_only__, 3, 4)); + __THROW __nonnull ((2, 3)) __wur + __fortified_attr_access (__write_only__, 3, 4); #endif /* Remove the link NAME. */ @@ -884,7 +887,7 @@ extern char *getlogin (void); This function is a possible cancellation point and therefore not marked with __THROW. */ extern int getlogin_r (char *__name, size_t __name_len) __nonnull ((1)) - __attr_access ((__write_only__, 1, 2)); + __fortified_attr_access (__write_only__, 1, 2); #endif #ifdef __USE_MISC @@ -906,7 +909,7 @@ extern int setlogin (const char *__name) __THROW __nonnull ((1)); The result is null-terminated if LEN is large enough for the full name and the terminator. */ extern int gethostname (char *__name, size_t __len) __THROW __nonnull ((1)) - __attr_access ((__write_only__, 1, 2)); + __fortified_attr_access (__write_only__, 1, 2); #endif @@ -925,7 +928,8 @@ extern int sethostid (long int __id) __THROW __wur; Called just like `gethostname' and `sethostname'. The NIS domain name is usually the empty string when not using NIS. */ extern int getdomainname (char *__name, size_t __len) - __THROW __nonnull ((1)) __wur __attr_access ((__write_only__, 1, 2)); + __THROW __nonnull ((1)) __wur + __fortified_attr_access (__write_only__, 1, 2); extern int setdomainname (const char *__name, size_t __len) __THROW __nonnull ((1)) __wur __attr_access ((__read_only__, 1, 2)); diff --git a/stdlib/stdlib.h b/stdlib/stdlib.h index 0481c12355..74c00eee73 100644 --- a/stdlib/stdlib.h +++ b/stdlib/stdlib.h @@ -943,7 +943,8 @@ extern size_t mbstowcs (wchar_t *__restrict __pwcs, extern size_t wcstombs (char *__restrict __s, const wchar_t *__restrict __pwcs, size_t __n) __THROW - __attr_access ((__write_only__, 1, 3)) __attr_access ((__read_only__, 2)); + __fortified_attr_access (__write_only__, 1, 3) + __attr_access ((__read_only__, 2)); #ifdef __USE_MISC /* Determine whether the string value of RESPONSE matches the affirmation @@ -997,7 +998,7 @@ extern char *ptsname (int __fd) __THROW __wur; terminal associated with the master FD is open on in BUF. Return 0 on success, otherwise an error number. */ extern int ptsname_r (int __fd, char *__buf, size_t __buflen) - __THROW __nonnull ((2)) __attr_access ((__write_only__, 2, 3)); + __THROW __nonnull ((2)) __fortified_attr_access (__write_only__, 2, 3); /* Open a master pseudo terminal and return its file descriptor. */ extern int getpt (void); diff --git a/string/bits/string_fortified.h b/string/bits/string_fortified.h index 67ae2c6b50..5731274848 100644 --- a/string/bits/string_fortified.h +++ b/string/bits/string_fortified.h @@ -64,7 +64,7 @@ __NTH (memset (void *__dest, int __ch, size_t __len)) # include void __explicit_bzero_chk (void *__dest, size_t __len, size_t __destlen) - __THROW __nonnull ((1)) __attr_access ((__write_only__, 1, 2)); + __THROW __nonnull ((1)) __fortified_attr_access (__write_only__, 1, 2); __fortify_function void __NTH (explicit_bzero (void *__dest, size_t __len)) @@ -106,7 +106,8 @@ __NTH (stpncpy (char *__dest, const char *__src, size_t __n)) #else extern char *__stpncpy_chk (char *__dest, const char *__src, size_t __n, size_t __destlen) __THROW - __attr_access ((__write_only__, 1, 3)) __attr_access ((__read_only__, 2)); + __fortified_attr_access ((__write_only__, 1, 3)) + __attr_access ((__read_only__, 2)); extern char *__REDIRECT_NTH (__stpncpy_alias, (char *__dest, const char *__src, size_t __n), stpncpy); diff --git a/string/string.h b/string/string.h index 04e1b7067d..8dcafb4ac4 100644 --- a/string/string.h +++ b/string/string.h @@ -448,7 +448,7 @@ extern char *strerror_l (int __errnum, locale_t __l) __THROW; /* Set N bytes of S to 0. The compiler will not delete a call to this function, even if S is dead after the call. */ extern void explicit_bzero (void *__s, size_t __n) __THROW __nonnull ((1)) - __attr_access ((__write_only__, 1, 2)); + __fortified_attr_access (__write_only__, 1, 2); /* Return the next DELIM-delimited token from *STRINGP, terminating it with a '\0', and update *STRINGP to point past it. */