This is an archive of the discontinued Mercurial Phabricator instance.

Differential D3698

chg: fix an undefined behavior about memcpy
ClosedPublic

Authored by quark on Jun 6 2018, 3:56 PM.

Details

Reviewers
None
Group Reviewers
hg-reviewers
Commits
rHG3c84493556db: chg: fix an undefined behavior about memcpy
Summary

Spot by Wez Furlong. memcpy(x, NULL, 0) is undefined according to [1].

[1]: https://stackoverflow.com/questions/5243012

Diff Detail

Repository
rHG Mercurial
Lint
Lint Skipped
Unit
Unit Tests Skipped

Event Timeline

quark created this revision.Jun 6 2018, 3:56 PM
quark edited the summary of this revision. (Show Details)Jun 6 2018, 3:58 PM
durin42 added a subscriber: durin42.Jun 6 2018, 4:02 PM

Lovely. Queued for stable, many thanks.

Closed by commit rHG3c84493556db: chg: fix an undefined behavior about memcpy (authored by quark). · Explain WhyJun 6 2018, 4:03 PM
This revision was automatically updated to reflect the committed changes.

Revision Contents
Changeset List

PathPackages
Mcontrib/chg/chg.c (5 lines)

Diff 8989

contrib/chg/chg.c

"--daemon-postexec", "--daemon-postexec",
"chdir:/", "chdir:/",
}; };
size_t baseargvsize = sizeof(baseargv) / sizeof(baseargv[0]); size_t baseargvsize = sizeof(baseargv) / sizeof(baseargv[0]);
size_t argsize = baseargvsize + opts->argsize + 1; size_t argsize = baseargvsize + opts->argsize + 1;
const char **argv = mallocx(sizeof(char *) * argsize); const char **argv = mallocx(sizeof(char *) * argsize);
memcpy(argv, baseargv, sizeof(baseargv)); memcpy(argv, baseargv, sizeof(baseargv));
memcpy(argv + baseargvsize, opts->args, sizeof(char *) * opts->argsize); if (opts->args) {
size_t size = sizeof(char *) * opts->argsize;
memcpy(argv + baseargvsize, opts->args, size);
}
argv[argsize - 1] = NULL; argv[argsize - 1] = NULL;
if (putenv("CHGINTERNALMARK=") != 0) if (putenv("CHGINTERNALMARK=") != 0)
abortmsgerrno("failed to putenv"); abortmsgerrno("failed to putenv");
if (execvp(hgcmd, (char **)argv) < 0) if (execvp(hgcmd, (char **)argv) < 0)
abortmsgerrno("failed to exec cmdserver"); abortmsgerrno("failed to exec cmdserver");
free(argv); free(argv);
} }