Date: Sat, 15 Jun 2024 09:39:35 +0000 From: bugzilla-noreply@freebsd.org To: bugs@FreeBSD.org Subject: [Bug 279762] libedit's cv_prev_word() can read before start of buffer Message-ID: <bug-279762-227@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D279762 Bug ID: 279762 Summary: libedit's cv_prev_word() can read before start of buffer Product: Base System Version: CURRENT Hardware: Any OS: Any Status: New Severity: Affects Only Me Priority: --- Component: bin Assignee: bugs@FreeBSD.org Reporter: rtm@lcs.mit.edu This code in contrib/libedit/chared.c cv_prev_word(): while (n--) { ...; test =3D (*wtest)(*p); while ((p >=3D low) && (*wtest)(*p) =3D=3D test) p--; The ">=3D" 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=20=20=20=20 root@stock14:/usr/obj/usr/src/amd64.amd64/sys/GENERIC amd64 --=20 You are receiving this mail because: You are the assignee for the bug.=
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