Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Sun, 30 Mar 2003 18:34:38 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Sun, 30 Mar 2003 18:34:38 -0500 Received: from slarti.muc.de ([193.149.48.10]:50698 "HELO slarti.muc.de") by vger.kernel.org with SMTP id ; Sun, 30 Mar 2003 18:34:34 -0500 From: Stephan Maciej Date: Sun, 30 Mar 2003 22:05:06 +0200 User-Agent: KMail/1.5.9 MIME-Version: 1.0 Content-Disposition: inline To: Linux Kernel Mailing List Subject: [PATCH 2.5.66 & 2.4.20] Fix sys_sethostname() and sys_setdomainname() Cc: Linus Torvalds , Marcelo Tosatti Content-Type: Multipart/Mixed; boundary="Boundary-00=_y30h+0J/yb/aXru" Message-Id: <200303302205.06770.stephanm@muc.de> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4699 Lines: 178 --Boundary-00=_y30h+0J/yb/aXru Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Content-Disposition: inline Hi, a long time ago someone mentioned that sethostname() and setdomainname() properly return -EFAULT when passing an invalid pointer to the new name, but instead of leaving the fields in system_utsname unchanged the nodename and domainname are set to an empty string. The behaviour of sys_sethostname() can be verified using the attached program (sethostname.c); sys_setdomainname() is almost the same so I guess that it has the same defect :-) The attached patches fix this. Stephan --Boundary-00=_y30h+0J/yb/aXru Content-Type: text/x-diff; charset="us-ascii"; name="sethostanddomainname-2.5.66.diff" Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename="sethostanddomainname-2.5.66.diff" --- kernel/sys.c~unmodified 2003-03-30 21:33:17.000000000 +0200 +++ kernel/sys.c 2003-03-30 21:43:20.000000000 +0200 @@ -1154,14 +1154,18 @@ asmlinkage long sys_sethostname(char *name, int len) { int errno; + char tmp[__NEW_UTS_LEN]; if (!capable(CAP_SYS_ADMIN)) return -EPERM; if (len < 0 || len > __NEW_UTS_LEN) return -EINVAL; + down_write(&uts_sem); errno = -EFAULT; - if (!copy_from_user(system_utsname.nodename, name, len)) { + + if (!copy_from_user(tmp, name, len)) { + memcpy(system_utsname.nodename, tmp, len); system_utsname.nodename[len] = 0; errno = 0; } @@ -1193,6 +1197,7 @@ asmlinkage long sys_setdomainname(char *name, int len) { int errno; + char tmp[__NEW_UTS_LEN]; if (!capable(CAP_SYS_ADMIN)) return -EPERM; @@ -1201,10 +1206,13 @@ down_write(&uts_sem); errno = -EFAULT; - if (!copy_from_user(system_utsname.domainname, name, len)) { - errno = 0; + + if (!copy_from_user(tmp, name, len)) { + memcpy(system_utsname.domainname, tmp, len); system_utsname.domainname[len] = 0; + errno = 0; } + up_write(&uts_sem); return errno; } --Boundary-00=_y30h+0J/yb/aXru Content-Type: text/x-csrc; charset="us-ascii"; name="sethostname.c" Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename="sethostname.c" #include #include #include #include #include int main() { int retval; char hostname[__NEW_UTS_LEN]; // Print out current hostname if ((retval = gethostname(hostname, __NEW_UTS_LEN)) == -1) { printf("call to gethostname() failed, retval=%d: %s\n", retval, strerror(errno)); return 1; }; printf("gethostname()=\"%s\"\n", hostname); // Set "new" hostname if ((retval = sethostname((char *)-1, 10)) != -1) { // We really EXPECT this to fail! printf("The Penguin is in trouble!\n"); return 2; } else printf("sethostname(INVALID, 10)=%d (error \"%s\")\n", retval, strerror(errno)); // And now once again: if ((retval = gethostname(hostname, __NEW_UTS_LEN)) == -1) { printf("call to gethostname() failed, retval=%d: %s\n", retval, strerror(errno)); return 1; }; printf("gethostname()=\"%s\"\n", hostname); return 0; }; --Boundary-00=_y30h+0J/yb/aXru Content-Type: text/x-diff; charset="us-ascii"; name="sethostanddomainname-2.4.20.diff" Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename="sethostanddomainname-2.4.20.diff" --- kernel/sys.c~unmodified 2003-03-30 21:51:07.000000000 +0200 +++ kernel/sys.c 2003-03-30 21:53:01.000000000 +0200 @@ -1026,6 +1026,7 @@ asmlinkage long sys_sethostname(char *name, int len) { int errno; + char tmp[__NEW_UTS_LEN]; if (!capable(CAP_SYS_ADMIN)) return -EPERM; @@ -1033,7 +1034,8 @@ return -EINVAL; down_write(&uts_sem); errno = -EFAULT; - if (!copy_from_user(system_utsname.nodename, name, len)) { + if (!copy_from_user(tmp, name, len)) { + memcpy(system_utsname.nodename, tmp, len); system_utsname.nodename[len] = 0; errno = 0; } @@ -1065,6 +1067,7 @@ asmlinkage long sys_setdomainname(char *name, int len) { int errno; + char tmp[__NEW_UTS_LEN]; if (!capable(CAP_SYS_ADMIN)) return -EPERM; @@ -1073,9 +1076,10 @@ down_write(&uts_sem); errno = -EFAULT; - if (!copy_from_user(system_utsname.domainname, name, len)) { - errno = 0; + if (!copy_from_user(tmp, name, len)) { + memcpy(system_utsname.domainname, tmp, len); system_utsname.domainname[len] = 0; + errno = 0; } up_write(&uts_sem); return errno; --Boundary-00=_y30h+0J/yb/aXru-- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/