Bug 279762
| Summary: | libedit's cv_prev_word() can read before start of buffer | ||
|---|---|---|---|
| Product: | Base System | Reporter: | Robert Morris <rtm> |
| Component: | bin | Assignee: | freebsd-bugs (Nobody) <bugs> |
| Status: | Open --- | ||
| Severity: | Affects Only Me | CC: | markj |
| Priority: | --- | ||
| Version: | CURRENT | ||
| Hardware: | Any | ||
| OS: | Any | ||
This should be addressed by https://github.com/NetBSD/src/commit/62c70a7281dc4f524b80aed6ef9cebc0b65d6ec0 |
This code in contrib/libedit/chared.c cv_prev_word(): while (n--) { ...; test = (*wtest)(*p); while ((p >= low) && (*wtest)(*p) == test) p--; The ">=" can cause p to be decremented even when it is equal to low, so that the next iteration of the outer loop dereferences an illegal p. If I run valgrind /bin/sh and type $ set -o vi then: ESC option-shift-s option-shift-3 2 b valgrind says: Invalid read of size 4 at 0x4873DA1: cv_prev_word (rtm/freebsd/contrib/libedit/chared.c:319) by 0x489C6D0: vi_prev_word (rtm/freebsd/contrib/libedit/vi.c:189) by 0x4889747: el_wgets (rtm/freebsd/contrib/libedit/read.c:540) by 0x4879B3C: el_gets (rtm/freebsd/contrib/libedit/eln.c:75) by 0x123D6E: preadfd (rtm/freebsd/bin/sh/input.c:138) by 0x12387A: preadbuffer (rtm/freebsd/bin/sh/input.c:210) by 0x1326C5: xxreadtoken (rtm/freebsd/bin/sh/parser.c:910) by 0x12E4FC: readtoken (rtm/freebsd/bin/sh/parser.c:827) by 0x12E379: parsecmd (rtm/freebsd/bin/sh/parser.c:222) by 0x129786: cmdloop (rtm/freebsd/bin/sh/main.c:206) by 0x1295D2: main (rtm/freebsd/bin/sh/main.c:167) Address 0x552186c is 4 bytes before a block of size 4,096 alloc'd at 0x4851735: calloc (vg_replace_malloc.c:1599) by 0x48740AA: ch_init (rtm/freebsd/contrib/libedit/chared.c:399) by 0x4877714: el_init_internal (rtm/freebsd/contrib/libedit/el.c:107) by 0x48775B0: el_init_fd (rtm/freebsd/contrib/libedit/el.c:124) by 0x487754A: el_init (rtm/freebsd/contrib/libedit/el.c:66) by 0x1215BC: histedit (rtm/freebsd/bin/sh/histedit.c:183) by 0x12C1ED: optschanged (rtm/freebsd/bin/sh/options.c:130) by 0x12BEA1: procargs (rtm/freebsd/bin/sh/options.c:121) by 0x1293EC: main (rtm/freebsd/bin/sh/main.c:131) FreeBSD stock14 15.0-CURRENT FreeBSD 15.0-CURRENT #22 main-n270479-ecd1d1f1dac4-dirty: Thu May 30 18:42:11 AST 2024 root@stock14:/usr/obj/usr/src/amd64.amd64/sys/GENERIC amd64