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-rw-r--r--Modules/getpath.c14
1 files changed, 10 insertions, 4 deletions
diff --git a/Modules/getpath.c b/Modules/getpath.c
index 10ad509..418c683 100644
--- a/Modules/getpath.c
+++ b/Modules/getpath.c
@@ -190,10 +190,14 @@ isdir(char *filename) /* Is directory */
}
-/* joinpath requires that any buffer argument passed to it has at
- least MAXPATHLEN + 1 bytes allocated. If this requirement is met,
- it guarantees that it will never overflow the buffer. If stuff
- is too long, buffer will contain a truncated copy of stuff.
+/* Add a path component, by appending stuff to buffer.
+ buffer must have at least MAXPATHLEN + 1 bytes allocated, and contain a
+ NUL-terminated string with no more than MAXPATHLEN characters (not counting
+ the trailing NUL). It's a fatal error if it contains a string longer than
+ that (callers must be careful!). If these requirements are met, it's
+ guaranteed that buffer will still be a NUL-terminated string with no more
+ than MAXPATHLEN characters at exit. If stuff is too long, only as much of
+ stuff as fits will be appended.
*/
static void
joinpath(char *buffer, char *stuff)
@@ -206,6 +210,8 @@ joinpath(char *buffer, char *stuff)
if (n > 0 && buffer[n-1] != SEP && n < MAXPATHLEN)
buffer[n++] = SEP;
}
+ if (n > MAXPATHLEN)
+ Py_FatalError("buffer overflow in getpath.c's joinpath()");
k = strlen(stuff);
if (n + k > MAXPATHLEN)
k = MAXPATHLEN - n;