cd: fix an invalid free() call (Solaris patch 211-21547336)

McDutchie · McDutchie · commit a3ccff6c7543 · 2021-01-08T12:43:19.000Z
This change is pulled from here: https://github.com/oracle/solaris-userland/blob/master/components/ksh93/patches/211-21547336.patch src/cmd/ksh93/bltins/cd_pwd.c: b_cd(): - The functions path_pwd() and path_relative() in sh/path.c may return a pointer to e_dot[] (".") as a fallback if they fail to determine a path. This is a string in read-only memory (data/msg.c), so must not be freed. A pointer to that string may end up in sh.pwd (== shp->pwd), so b_cd() needs a check for that.
diff --git a/src/cmd/ksh93/bltins/cd_pwd.c b/src/cmd/ksh93/bltins/cd_pwd.c
@@ -212,7 +212,7 @@ int	b_cd(int argc, char *argv[],Shbltin_t *context)
 	nv_scan(sh_subtracktree(1),rehash,(void*)0,NV_TAGGED,NV_TAGGED);
 	path_newdir(shp,shp->pathlist);
 	path_newdir(shp,shp->cdpathlist);
-	if(oldpwd)
+	if(oldpwd && oldpwd!=e_dot)
 		free(oldpwd);
 	return(0);
 }

Original file line number	Diff line number	Diff line change
`@@ -212,7 +212,7 @@ int b_cd(int argc, char argv[],Shbltin_t context)`
`212`	`212`	`nv_scan(sh_subtracktree(1),rehash,(void*)0,NV_TAGGED,NV_TAGGED);`
`213`	`213`	`path_newdir(shp,shp->pathlist);`
`214`	`214`	`path_newdir(shp,shp->cdpathlist);`
`215`		`- if(oldpwd)`
	`215`	`+ if(oldpwd && oldpwd!=e_dot)`
`216`	`216`	`free(oldpwd);`
`217`	`217`	`return(0);`
`218`	`218`	`}`