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lib: sbi: Fix timing of clearing tbuf

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A single scan of the format char may add multiple characters to the
tbuf, causing a buffer overflow. You should check if tbuf is full in
printc so that it does not cause a buffer overflow.

Signed-off-by: Xiang W <wxjstz@126.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
This commit is contained in:
Xiang W 2023-07-10 00:02:30 +08:00 • committed by Anup Patel
parent cc89fa7b54
commit ff43168137
1 changed files with 19 additions and 16 deletions
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35
lib/sbi/sbi_console.c
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@ -121,6 +121,7 @@ unsigned long sbi_ngets(char *str, unsigned long len)
#define PAD_ZERO 2
#define PAD_ALTERNATE 4
#define PAD_SIGN 8
#define USE_TBUF 16
#define PRINT_BUF_LEN 64
#define va_start(v, l) __builtin_va_start((v), l)
@ -128,7 +129,7 @@ unsigned long sbi_ngets(char *str, unsigned long len)
#define va_arg __builtin_va_arg
typedef __builtin_va_list va_list;
static void printc(char **out, u32 *out_len, char ch)
static void printc(char **out, u32 *out_len, char ch, int flags)
{
if (!out) {
sbi_putc(ch);
@ -142,8 +143,14 @@ static void printc(char **out, u32 *out_len, char ch)
if (!out_len || *out_len > 1) {
*(*out)++ = ch;
**out = '\0';
if (out_len)
if (out_len) {
--(*out_len);
if ((flags & USE_TBUF) && *out_len == 1) {
nputs_all(console_tbuf, CONSOLE_TBUF_MAX - *out_len);
*out = console_tbuf;
*out_len = CONSOLE_TBUF_MAX;
}
}
}
}
@ -154,16 +161,16 @@ static int prints(char **out, u32 *out_len, const char *string, int width,
width -= sbi_strlen(string);
if (!(flags & PAD_RIGHT)) {
for (; width > 0; --width) {
printc(out, out_len, flags & PAD_ZERO ? '0' : ' ');
printc(out, out_len, flags & PAD_ZERO ? '0' : ' ', flags);
++pc;
}
}
for (; *string; ++string) {
printc(out, out_len, *string);
printc(out, out_len, *string, flags);
++pc;
}
for (; width > 0; --width) {
printc(out, out_len, ' ');
printc(out, out_len, ' ', flags);
++pc;
}
@ -215,18 +222,18 @@ static int printi(char **out, u32 *out_len, long long i,
if (flags & PAD_ZERO) {
if (sign) {
printc(out, out_len, sign);
printc(out, out_len, sign, flags);
++pc;
--width;
}
if (i && (flags & PAD_ALTERNATE)) {
if (b == 16 || b == 8) {
printc(out, out_len, '0');
printc(out, out_len, '0', flags);
++pc;
--width;
}
if (b == 16) {
printc(out, out_len, 'x' - 'a' + letbase);
printc(out, out_len, 'x' - 'a' + letbase, flags);
++pc;
--width;
}
@ -265,15 +272,11 @@ static int print(char **out, u32 *out_len, const char *format, va_list args)
}
for (; *format != 0; ++format) {
if (use_tbuf && !console_tbuf_len) {
nputs_all(console_tbuf, CONSOLE_TBUF_MAX);
console_tbuf_len = CONSOLE_TBUF_MAX;
tout = console_tbuf;
}
width = flags = 0;
if (use_tbuf)
flags |= USE_TBUF;
if (*format == '%') {
++format;
width = flags = 0;
if (*format == '\0')
break;
if (*format == '%')
@ -371,7 +374,7 @@ static int print(char **out, u32 *out_len, const char *format, va_list args)
}
} else {
literal:
printc(out, out_len, *format);
printc(out, out_len, *format, flags);
++pc;
}
}