From a5f5415eae9f70df9dd4633656cac7a3b88985b9 Mon Sep 17 00:00:00 2001
From: Michael Moore <github@imichael.org>
Date: Sat, 29 Nov 2025 11:47:19 -0700
Subject: [PATCH] fix: improve slurp() robustness with size limit and read loop

Addresses several issues in slurp():

1. No size limit - A large dependency file could exhaust memory
2. Partial reads - read() can return fewer bytes than requested
3. EINTR - Interrupted system calls weren't retried

Fix:
- Add 10MB size limit (SLURP_MAX_SIZE)
- Read in a loop until all bytes are received
- Retry on EINTR
- Log malloc failures

Note: Preserves the TOCTOU fix from PR #9 (fstat after open).
---
 src/job.c | 35 +++++++++++++++++++++++++----------
 1 file changed, 25 insertions(+), 10 deletions(-)

diff --git a/src/job.c b/src/job.c
index 355a490..5786969 100644
--- a/src/job.c
+++ b/src/job.c
@@ -345,10 +345,13 @@ char *fpath(job_t *job, char *file) {
 }
 
 /* this function reads a whole file into a malloc'd buffer */
+#define SLURP_MAX_SIZE (10 * 1024 * 1024)  /* 10 MB limit */
 int slurp(char *file, char **text, size_t *len) {
   struct stat s;
   char *buf;
-  int fd = -1, rc=-1, nr;
+  int fd = -1, rc=-1;
+  ssize_t nr;
+  size_t total = 0;
   *text=NULL; *len = 0;
 
   if ( (fd = open(file, O_RDONLY)) == -1) {
@@ -361,15 +364,27 @@ int slurp(char *file, char **text, size_t *len) {
   }
   *len = s.st_size;
   if (*len == 0) {rc=0; goto done;} // special case, empty file
-  if ( (*text = malloc(*len)) == NULL) goto done;
-  if ( (nr=read(fd, *text, *len)) != *len) {
-   if (nr == -1) {
-     syslog(LOG_CRIT,"read %s failed: %s", file, strerror(errno));
-   } else {
-     syslog(LOG_CRIT,"read %s failed: incomplete (%u/%u)", file, 
-        nr, (unsigned)*len);
-   }
-   goto done;
+  if (*len > SLURP_MAX_SIZE) {
+    syslog(LOG_ERR,"%s: file too large (%zu bytes)", file, *len);
+    goto done;
+  }
+  if ( (*text = malloc(*len)) == NULL) {
+    syslog(LOG_ERR,"malloc failed for %s", file);
+    goto done;
+  }
+  while (total < *len) {
+    nr = read(fd, *text + total, *len - total);
+    if (nr == -1) {
+      if (errno == EINTR) continue;
+      syslog(LOG_CRIT,"read %s failed: %s", file, strerror(errno));
+      goto done;
+    }
+    if (nr == 0) {
+      syslog(LOG_CRIT,"read %s failed: unexpected EOF (%zu/%zu)", file,
+         total, *len);
+      goto done;
+    }
+    total += nr;
   }
   rc = 0;