saimaa: sblmain stack-pc override prop; sbl analysis tools

2026-09-07 09:28:02 +00:00
parent 61cb6b9db3
commit 5f14a0eac5
4 changed files with 150 additions and 0 deletions
@@ -0,0 +1,52 @@
+#!/usr/bin/env python3
+"""sbl_adr.py — поиск ADR (ADD/SUB pc) ссылок на интересные строки SBL1.
+Использование: ./tools/sbl_adr.py fw/sbl/img0.elf
+"""
+import struct
+import sys
+
+d = open(sys.argv[1], "rb").read()
+STRINGS = [b"SBL1, Start", b"SBL1, End", b"SBL1, Delta",
+           b"Sahara: Hello pkt sent", b"bl_power_on", b"sbl1_main"]
+svas = {}
+for s in STRINGS:
+    i = d.find(s)
+    if i < 0:
+        continue
+    # find which segment contains it
+    phoff = struct.unpack("<I", d[28:32])[0]
+    phnum = struct.unpack("<H", d[44:46])[0]
+    for k in range(phnum):
+        p = d[phoff + k * 32:phoff + (k + 1) * 32]
+        t, off, v, pa, fsz, msz, fl, al = struct.unpack("<IIIIIIII", p)
+        if t == 1 and off <= i < off + fsz:
+            svas[s] = v + (i - off)
+for s, va in svas.items():
+    print(s.decode(), "VA:", hex(va))
+
+phoff = struct.unpack("<I", d[28:32])[0]
+phnum = struct.unpack("<H", d[44:46])[0]
+segs = []
+for k in range(phnum):
+    p = d[phoff + k * 32:phoff + (k + 1) * 32]
+    t, off, v, pa, fsz, msz, fl, al = struct.unpack("<IIIIIIII", p)
+    if t == 1 and fsz and (fl & 1 or True):
+        segs.append((off, v, fsz))
+for s, va in svas.items():
+    print("--- refs to", s.decode(), hex(va))
+    n = 0
+    for off, v, sz in segs:
+        code = d[off:off + sz]
+        for j in range(0, len(code) - 4, 4):
+            x = struct.unpack("<I", code[j:j + 4])[0]
+            # ADD Rd,pc,#imm12 rotated; SUB Rd,pc,#imm
+            if (x & 0x0FFF0000) in (0x028F0000, 0x024F0000):
+                imm = x & 0xFFF
+                rot = (x & 0xF00) >> 7
+                imm = ((imm >> rot) | (imm << (32 - rot))) & 0xFFFFFFFF if rot else imm
+                tgt = (v + j + 8 + (imm if (x & 0x400000) else -imm)) & 0xFFFFFFFF
+                if abs(tgt - va) < 0x100:
+                    print("  ", hex(v + j), "->", hex(tgt))
+                    n += 1
+                    if n > 6:
+                        break