Overengineer a fix for the EDL UB slop

common/common.h

@@ -22,6 +22,7 @@
 #include <stdlib.h>
 #include <stdbool.h>
 #include <stdint.h>
+#include <limits.h>
 
 #include "config.h"
 
@@ -65,6 +66,27 @@
 // Return a+b, unless a is NOPTS. b must not be NOPTS.
 #define MP_ADD_PTS(a, b) ((a) == MP_NOPTS_VALUE ? (a) : ((a) + (b)))
 
+// Return the maximum value representable by integer type of a.
+#define MP_MAX_VAL(a) _Generic((a),                             \
+                               char: SCHAR_MAX,                 \
+                               unsigned char: UCHAR_MAX,        \
+                               short: SHRT_MAX,                 \
+                               unsigned short: USHRT_MAX,       \
+                               int: INT_MAX,                    \
+                               unsigned int: UINT_MAX,          \
+                               long: LONG_MAX,                  \
+                               unsigned long: ULONG_MAX,        \
+                               long long: LLONG_MAX,            \
+                               unsigned long long: ULLONG_MAX)
+
+// Multiply a * b and store in result. If result would overflow, saturate at
+// its maximum value instead, and return true. Otherwise, return false.
+#define MP_SATURATE_MUL(result, a, b) (         \
+    MP_CKD_MUL(result, a, b) ?                  \
+        *result = MP_MAX_VAL(*result), true :   \
+        false                                   \
+)
+
 #define CONTROL_OK 1
 #define CONTROL_TRUE 1
 #define CONTROL_FALSE 0

demux/demux_edl.c

@@ -243,7 +243,7 @@ static struct tl_root *parse_edl(bstr str, struct mp_log *log)
                     : get_meta(tl, index);
                 sh->lang = get_param0(&ctx, sh, "lang");
                 sh->title = get_param0(&ctx, sh, "title");
-                sh->hls_bitrate = get_param_int(&ctx, "byterate", 0) * 8;
+                MP_SATURATE_MUL(&sh->hls_bitrate, get_param_int(&ctx, "byterate", 0), 8);
                 int pid = get_param_int(&ctx, "program_id", -1);
                 if (pid >= 0)
                     MP_TARRAY_APPEND(sh, sh->program_ids, sh->num_program_ids, pid);

osdep/compiler.h

@@ -7,6 +7,7 @@
 #define MP_EXPAND_ARGS(...) __VA_ARGS__
 
 #if defined(__STDC_VERSION__) && __STDC_VERSION__ >= 202311L
+#include <stdckdint.h>
 #define MP_NORETURN [[noreturn]]
 #define MP_FALLTHROUGH [[fallthrough]]
 #define MP_WARN_UNUSED_RESULT [[nodiscard]]
@@ -78,4 +79,10 @@
 #define MP_SCANF_ATTRIBUTE(a1, a2)
 #endif
 
+#if defined(__STDC_VERSION_STDCKDINT_H__) && __STDC_VERSION_STDCKDINT_H__ >= 202311L
+#define MP_CKD_MUL(result, a, b) ckd_mul(result, a, b)
+#elif __has_builtin(__builtin_mul_overflow)
+#define MP_CKD_MUL(result, a, b) __builtin_mul_overflow(a, b, result)
+#endif
+
 #endif