From b9424f640a0493359fd2af7c670c5a4ced334e6b Mon Sep 17 00:00:00 2001 From: Fazlul Shahriar Date: Thu, 19 Sep 2019 13:08:54 -0400 Subject: plumber: fix EOF detection on writes to rules file (#257) Instead of checking Fcall.data==nil, check Fcall.count==0. The former check always fails after `gcc -O2` optimizations (gcc version 8.3.0). Also fix an out-of-bound read detected by valgrind: ``` ==31162== Invalid read of size 1 ==31162== at 0x11005E: morerules (rules.c:739) ==31162== by 0x110254: writerules (rules.c:775) ==31162== by 0x10D2FE: fsyswrite (fsys.c:848) ==31162== by 0x10C304: fsysproc (fsys.c:248) ==31162== by 0x112E8C: threadstart (thread.c:96) ==31162== by 0x4A682BF: ??? (in /usr/lib/libc-2.29.so) ==31162== Address 0x4ea984a is 0 bytes after a block of size 250 alloc'd ==31162== at 0x483AD7B: realloc (vg_replace_malloc.c:826) ==31162== by 0x1196F3: p9realloc (malloc.c:53) ==31162== by 0x10BDFD: erealloc (plumber.c:124) ==31162== by 0x10FCD9: concat (rules.c:642) ==31162== by 0x10FCD9: concat (rules.c:635) ==31162== by 0x110230: writerules (rules.c:773) ==31162== by 0x10D2FE: fsyswrite (fsys.c:848) ==31162== by 0x10C304: fsysproc (fsys.c:248) ==31162== by 0x112E8C: threadstart (thread.c:96) ==31162== by 0x4A682BF: ??? (in /usr/lib/libc-2.29.so) ``` Fixes #256 --- src/cmd/plumb/rules.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/src/cmd/plumb/rules.c b/src/cmd/plumb/rules.c index 4da4bb23..6e9b2c63 100644 --- a/src/cmd/plumb/rules.c +++ b/src/cmd/plumb/rules.c @@ -736,8 +736,8 @@ morerules(uchar *text, int done) */ endofrule = nil; for(s=text; *s!='\0'; s++) - if(*s=='\n' && *++s=='\n') - endofrule = s+1; + if(*s=='\n' && *(s+1)=='\n') + endofrule = s+2; if(endofrule == nil) return text; input->end = endofrule; @@ -772,7 +772,7 @@ writerules(char *s, int n) tmp = stringof(s, n); text = (uchar*)concat((char*)text, tmp); free(tmp); - text = morerules(text, s==nil); + text = morerules(text, n==0); } if(s == nil){ free(text); -- cgit v1.2.3