Messages in this thread | | | Subject | Re: [PATCH] driver: of: Properly truncate command line if too long | From | Alex Ghiti <> | Date | Tue, 6 Apr 2021 10:53:17 -0400 |
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Le 4/6/21 à 9:40 AM, Rob Herring a écrit : > On Sat, Apr 3, 2021 at 7:09 AM Alex Ghiti <alex@ghiti.fr> wrote: >> >> Hi, >> >> Le 3/16/21 à 3:38 PM, Alexandre Ghiti a écrit : >>> In case the command line given by the user is too long, warn about it >>> and truncate it to the last full argument. >>> >>> This is what efi already does in commit 80b1bfe1cb2f ("efi/libstub: >>> Don't parse overlong command lines"). >>> >>> Reported-by: Dmitry Vyukov <dvyukov@google.com> >>> Signed-off-by: Alexandre Ghiti <alex@ghiti.fr> >>> --- >>> drivers/of/fdt.c | 21 ++++++++++++++++++++- >>> 1 file changed, 20 insertions(+), 1 deletion(-) >>> >>> diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c >>> index dcc1dd96911a..de4c6f9bac39 100644 >>> --- a/drivers/of/fdt.c >>> +++ b/drivers/of/fdt.c >>> @@ -25,6 +25,7 @@ >>> #include <linux/serial_core.h> >>> #include <linux/sysfs.h> >>> #include <linux/random.h> >>> +#include <linux/ctype.h> >>> >>> #include <asm/setup.h> /* for COMMAND_LINE_SIZE */ >>> #include <asm/page.h> >>> @@ -1050,9 +1051,27 @@ int __init early_init_dt_scan_chosen(unsigned long node, const char *uname, >>> >>> /* Retrieve command line */ >>> p = of_get_flat_dt_prop(node, "bootargs", &l); >>> - if (p != NULL && l > 0) >>> + if (p != NULL && l > 0) { >>> strlcpy(data, p, min(l, COMMAND_LINE_SIZE)); >>> >>> + /* >>> + * If the given command line size is larger than >>> + * COMMAND_LINE_SIZE, truncate it to the last complete >>> + * parameter. >>> + */ >>> + if (l > COMMAND_LINE_SIZE) { >>> + char *cmd_p = (char *)data + COMMAND_LINE_SIZE - 1; >>> + >>> + while (!isspace(*cmd_p)) >>> + cmd_p--; >>> + >>> + *cmd_p = '\0'; >>> + >>> + pr_err("Command line is too long: truncated to %d bytes\n", >>> + (int)(cmd_p - (char *)data + 1)); >>> + } >>> + } >>> + >>> /* >>> * CONFIG_CMDLINE is meant to be a default in case nothing else >>> * managed to set the command line, unless CONFIG_CMDLINE_FORCE >>> >> >> Any thought about that ? > > It looks fine to me, but this will need to be adapted to the generic > command line support[1][2] when that is merged. So I've been waiting > to see if that's going to happen this cycle.
Ok I'll take a look then, thanks.
Alex
> > Rob > > [1] https://lore.kernel.org/lkml/cover.1616765869.git.christophe.leroy@csgroup.eu/ > [2] https://lore.kernel.org/lkml/41021d66db2ab427c14255d2a24bb4517c8b58fd.1617126961.git.danielwa@cisco.com/ >
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