Date: Sat, 26 Jan 2019 20:43:28 +0000 (UTC) From: Stefan Esser <se@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r343479 - head/libexec/getty Message-ID: <201901262043.x0QKhS2S081625@repo.freebsd.org>
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Author: se Date: Sat Jan 26 20:43:28 2019 New Revision: 343479 URL: https://svnweb.freebsd.org/changeset/base/343479 Log: Fix potential buffer overflow and undefined behavior. The buffer allocated in read_chat() could be 1 element too short, if the chatstr parameter passed in is 1 or 3 charachters long (e.g. "a" or "a b"). The allocation of the pointer array does not account for the terminating NULL pointer in that case. Overlapping source and destination strings are undefined in strcpy(). Instead of moving a string to the left by one character just increment the char pointer before it is assigned to the results array. MFC after: 2 weeks Modified: head/libexec/getty/chat.c Modified: head/libexec/getty/chat.c ============================================================================== --- head/libexec/getty/chat.c Sat Jan 26 18:23:19 2019 (r343478) +++ head/libexec/getty/chat.c Sat Jan 26 20:43:28 2019 (r343479) @@ -141,7 +141,7 @@ read_chat(char **chatstr) int l; if ((l=strlen(str)) > 0 && (tmp=malloc(l + 1)) != NULL && - (res=malloc((l / 2 + 1) * sizeof(char *))) != NULL) { + (res=malloc(((l + 1) / 2 + 1) * sizeof(char *))) != NULL) { static char ws[] = " \t"; char * p; @@ -216,7 +216,7 @@ read_chat(char **chatstr) q = strrchr(p+1, *p); if (q != NULL && *q == *p && q[1] == '\0') { *q = '\0'; - strcpy(p, p+1); + p++; } }
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